The best apps to buy with your Christmas iTunes vouchers

With a crisp virtual £50 note, you can go for higher-priced apps that you might otherwise avoid.

At £5.99 each, there's Air Sharing Pro, which turns your device into a wireless drive and enables you to view many document types, Documents To Go, a mobile version of Office, and Things, an innovative and polished task manager.

If your thoughts post-holiday turn to getting trim, RunKeeper Pro is a must. Another £5.99 app, it enables you to use an iPhone for tracking via GPS walks, runs and other forms of exercise, and results are compiled on the RunKeeper website. Think Nike+, but for under six quid.

And to keep eating more healthily, consider Jamie's 20 Minute Meals (£4.99): 50 simple, tasty step-by-step recipes, along with guides and shopping lists.

GET FIT: RunKeeper Pro is like Nike+, but better - and only six quid

When it's time to kick back and relax, try Eucalyptus (£5.99), the App Store's premier eReader, which grabs content from Project Gutenberg.

Its interface is the closest you'll get to a real book on your device. Also check out Simplify Music 2 (£4.99), which enables you to stream your media collection over the internet, circumventing your device's relatively small capacity.

Finally, treat yourself to some of the App Store's more advanced games - top golfing effort Tiger Woods PGA Tour (£2.99), evolving blaster Space Invaders Infinity Gene (£2.99), and the recently released update of classic PlayStation '70s cop show racer Driver (£3.99).

SHOOT 'EM UP: Space Invaders Infinity Gene should be used as a rulebook in how to bring a much-loved franchise into the present