AVG Internet Security 2011
Price: £38 (one PC)
AVG is best known for its free antivirus, but this commercial version offers more than a few reasons to upgrade, including identity protection and a built-in firewall.
Still, install it and you could be forgiven for thinking it's still trying to upsell you on a later version, because it's more than a little eager to make sure you know everything it's doing. It adds a Gadget to the Windows Sidebar, its firewall is very noticeable, and it can feel like the smart kid at the front of the class going "Sir! Sir! I know, sir!"
Still, it performs well enough for a pat on the head. In tests, it was easily the fastest of the tools here on first scan, and an excellent performer on subsequent scans. It demands fairly high CPU usage, but barely affected rebooting times at all.
On the all-important virus test, it was a clean sweep for both actual malware and false-positives. The only real weaknesses are the Link Scanner, which protects you from malicious sites and sending out dodgy links via Facebook, but only in internet Explorer and Firefox, and it's not always clear exactly what its options will do for you – the Identity Protection component being particularly vague.
AVG is a strong contender, although for personal use, it must be noted that if it's only the antivirus side of the package that you're interested in, you can still download it for free. (For professional/corporate use, you need to pay up for the full package.)
The main things you miss out on if you opt for the free version are the firewall, anti-spam (which you probably won't use since it's clientside only), IM conversation scanning, and the Identity Protection component.