Yesterday we told you about the seven things you won't like about Mac OS X 10.5 Leopard. Now it's my turn to point out the good stuff...

1. Quick Look

Easily the best feature of the reinvigorated Finder, Quick Look gives you a sneak peek at the contents of a file without you physically having to open it in an application. It works with any kind of file, but is most useful for documents, presentations and spreadsheets where the new thumbnail previews doesn't always give you much of a clue about their contents.

Of course Quick Look works with pictures and movies too, and even enables you to play movies right in the Finder without forcing you top open QuickTime, iTunes, etc.

Quick Look functionality is buried deep into the OS, enabling you to take advantage of it in any of the Finder views (it finds its best expression in the Cover Flow view). It even works in some apps - you can look use it to look at attachments in Mail, for example, as well as backed up files in Time Machine.

Quick Look can even handle multi-page documents. Open a PDF in Quick Look and scroll bars appear on the right side of its translucent window, enabling you to peek at every page. Ditto for picture selections.

Best of all Quick Look is fast to access - while you can mouse click over the icon in a Finder window, it's much speedier just to tap the Spacebar.

2. Time Machine

Leopard's killer feature is an automated backup program. It's aimed at people who know they should back up their precious files but either don't know how to; or are simply put off by the intimidating nature of most backup programs. The exception to this rule on the Mac is SuperDuper, which manages to balance simplicity with power.

Briefly, Time Machine backs up everything on your Mac when you first switch it on (a big 'on' switch is exactly all it takes). Then it makes incremental backups every hour, every day and every week until your backup drive is full. Backup drives can either be external FireWire 400, FireWire 800 and USB HDDs, or spare internal drives - the Mac Pro can hold up to four.

Apple has deliberately limited your customisation options to keep Time Machine simple. You can prevent certain files, folders or even disks from being backed up by selecting the Options tab in System Preferences > Time Machine. You can also set it to warn you when old backups are deleted. So far, so good.

Time Machine proves its worth when you want to resurrect a file you've accidentally deleted. To do that you simply click on the Time Machine icon in the Dock.

The application then magically glides into view, complete with geeky moving starfield and 3D view of previous Finder views stretching back in history to the time of your first full backup. You'll also see time represented as a series of marks - like on a ruler - running up the right side of the screen.

Right, remember that file you deleted? To find the last version you can either simply go back through time until you find it, or search for it using Spotlight, Apple's desktop search tool. When you do find the file, simply select it and then press the Spacebar to get a Quick Look view. To bring it back to the present, simply click on Restore and you're done.

File backup and restoration is rarely fun. In Mac OS X 10.5 Leopard it's an absolute treat.

3. Spaces

Virtual desktops are nothing new on either on the Mac or PC. The basic idea is that you can set up multiple desktops - up to 16, but four by default - that enables you to free up precious disk space. You can keep Mail and Safari in one space, for example, iPhoto in another, iTunes in a third and games in a fourth. Sounds confusing? In Leopard it's very practical.

This is chiefly because Spaces is very accessible. There five different ways you can call it to action:

• By clicking on its icon in the Dock
• By clicking on its optional icon in the Finder menu bar the top of the screen
• By pressing F8 (or any other key you choose)
• By pressing Ctrl and the cursor keys to navigate between spaces
• By picking a hot corner in the bottom left, bottom right, top left or top right of the screen

There's also a sixth action that enables you to navigate straight to a space that a particular application is in: just click on that application's icon in the Dock.

Spaces is also very flexible - you can move files and applications from one virtual desktop to another, by pressing F8 and then dragging and dropping the item that you wish to move. We've been using Spaces solid for four days now and it works very well indeed.

4. Mail

Version 3.0 of Apple's email application Mail is by far the most polished and powerful yet. It sports the new unified look of the rest of Mac OS X 10.5 Leopard and has three headline features - Stationery, Notes and To Dos.

Stationery contains over 25 HTML themed templates to jazz up your emails. Each template contains placeholder text and images that you can simply overwrite with your own selections - great then for sending baby pictures around the family, less good for writing a formal email to a business contact.

Notes and To Dos are variations on a theme. Notes enables you to write a message to yourself as a reminder. It pops up in a Notes folder in the sidebar and sits there until you decide to delete it. You can then add a To Do, which is also duplicated in iCal. To Dos also appear in their own folder in Mail's sidebar.

The next bit is really clever. Apple has included something it calls Data Detectors in Mail that automatically identify addresses, phone numbers and diary dates so you can add them to the Address Book or iCal.

To add a phone number for example you simply hover over it and a Data Detector menu appears. It gives you the option to create a new contact or add information to an existing one. You can then edit how and where the information will appear in Address Book right in the Mail app.

Date data detectors enable you to add the event to iCal or check your schedule for the day on which the event is to take place. Data detectors can even tell relative dates apart - say you received an email on Friday 26th in which someone writes, "See you at 10am next Wednesday", the data detectors will know to place the event in your calendar at the correct time, on the correct day and on the correct date.

Data detectors aren't without their flaws. You'll hunt in vain for a detector to pick up the name of a person or company. It also sometimes struggles with addresses, especially of some of the more exotic ones we have in the UK. As a first effort data detectors work indecently well - we'll be using them a lot.

Other new features include an RSS reader right within Mail, plus improved smart searches using Spotlight - something that already worked very well under Mac OS X 10.4 Tiger. We can't imagine why you'd want to use any other email application in Mac OS X. Microsoft's Entourage blows a big one by comparison.

5. iCal

Mail's increasingly grown-up feature set is reflected by notable improvements in iCal. The revamped app is smarter, iCal loads much quicker, and thanks to third-party apps like Spanning Sync can even be used to read / write entries in online calendars like Google Calendar.

Like many Apple apps in Leopard, iCal has also literally dropped its drawers - the side-mounted pop-out used to contain additional info, folders, etc., iCal's old drawer has been replaced with much more elegant inline editing of events, which is now quick and simple. You can even add photos, movies and other information to an event - enabling invitees to a meeting you're holding to see the agenda beforehand. You can even book a conference room and equipment using iCal's CalDAV integration.

Who says the Mac isn't ready for enterprise?

6. Front Row

Apple's answer to Microsoft's Windows Media Center Edition took a long time coming. At first Jobs was dismissive of MCE, and then in October 2005 the first Macs started shipping with their own remote controls and Front Row - a simple Mac alternative to MCE.

The version included in Leopard though is all new. It's been lifted from Apple TV and is quick, slick and lovely to look at. You don't even need an Apple remote to use it - it can be invoked either by clicking on its application in the Dock or by pressing the Command (Apple) and Esc key at the same time.

Front Row gives you access to any QuickTime compatible movies stored on your home network, can playback podcasts and songs from iTunes, even display your photos as a full screen slideshow. Apple is clearly playing catch-up with MCE here, but it's done so in a way that's very pleasurable to use.

7. Speed and responsiveness

We've been playing with Leopard on both a 64-bit Power Mac G5 and a 32-bit Intel-based MacBook Pro. Given that Leopard is now pre-eminently a 64-bit OS, and Intel's been kicking butt in the CPU space, we should be seeing some Leopard fur fly, shouldn't we?

Certainly every other version of Mac OS X has bested the predecessor when it comes to outright speed. On our MacBook Pro, Leopard is fast and stable. It boots up from a cold start in just 29 seconds, while applications like Address Book, iCal and Mail open up in a couple of bounces of their icon in the Dock.

Unsurprisingly the slowest apps are the those Carbon-based ones that are running on the Core 2 Duo using Rosetta - Apple's PowerPC emulation app. Microsoft Word 2004 for Mac, for example, takes eight bounces to launch. Adobe Photoshop Elements is around the same.

Things are currently less clear-cut with the PowerPC version even with its two 64-bit 2GHz processor on board. We're still evaluating its performance. We'll bring you our conclusions in our full Mac OS X 10.5 Leopard review coming soon.