While I may not agree with Suvega's "just make sure you update" philosophy, I'd say I'd agree with the argument that...

"Just run x browser" <-- bad argument.

"Make sure your computer is up-to-date" <-- good advice, but not 100% either

NO browser is foolproof, and putting all your eggs in the browser fanboi basket (whether you prefer one or the other) is generally a dumb idea. Using your browser (whichever it is) PROPERLY and utilizing proper 'netiquette is the REAL solution -- though, like Fur said, the chances of that happening is pretty slim given the typical "I want it, I want it now, I don't care" attitude that we've grown into thanks to having everything on the 'web just a click away.

So yea, I'd agree with Suvega that "Just use firefox" was bad advice -- I also agree that "Just use IE8" would be similar bad advice -- regular virus scanning, safe browsing habits, and a proper backup plan when viruses do happen is a more realistic solution.

I think Firefox's reputation as the anti-virus browser is a bit of a stretch -- it may be slightly better or slightly worse, but let's remember that the current state of affairs in the virus world is dynamically changing, so the percentile rate of infection may be low now, and may not be in the future -- we don't know. Telling someone "If you use Firefox, you won't get viruses" is just false advertisement. "Firefox has a x% smaller chance of virus infections over the past y months" is more appropriate -- I honestly don't know the numbers here, nor how they relate to IE/Safari, but at the very least "Firefox has a history of fewer/more viruses compared to x browser" is still more appropriate. Regardless, it's totally irrelevant to the OP's problem since we neither know which browser they're using nor whether the issue was related to browser insecurities or something else -- the OP's trying to help people by giving them fair warning, so dragging your favorite browser advertisement speech is a bit off-topic.

Unless you're totally unplugged from the outside world, the reality is that viruses continue to adapt and that, sometime and someday - IE or Firefox - scripts or noscripts, you will probably get one even with careful planning. So, like the OP seems to be doing with reimaging his machine, it's best to make regular backups of important files and be prepared when that sneaky little virus does rear its ugly head on your system.