>Firefox as it is targetted less by malware
Got caught by one – despite using Firefox (yes, it is a little better) last wednesday (annoyingly as I was trying to pitch in for the free Rage Against The Machine tickets). In another tab I'd been looking at coverage on a company product -some fansite of other – and picked up some spyware. A few giveaways – pinged up a warning that looked vaguely kosher but didn't ring true particularly compared to other occasions when MCafee's found something – plus there was now a little shield on the toolbar with a related dialog box that I didn't recognise. Tried to kick off McAfee but that was reported corrupted – yet a search for changed files for that day didn't show it as such – very suspicious. Didn't dare touch anything apart from pulling the network cable, rebooting and getting our IT bod. Spybot in safe mode (IIRC) found it, simply deleting the relevant (new) subdirectory worked, following scan was clean.
I suspect the worst thing you can do…well, other than handing over credit card details 😉 – is to start clicking popup dialogs, you can't trust what's real and what the virus is generating