Mac Anti-Virus...

I use MacKeeper on my Mac and its a greta piece of software, however I have never used the AntiVirus function. Never had the need. Remember Macs very rarely get viruses. If you use your mac with care and don't go downloading illegal software and dodgy files you will be ok. I have never had any problems.

I use Kaspersky Internet Security 2011 on my Windows 7 computer, and I like it a lot. So if it is somewhat the same then Kaspersky would be a good plan to have on the Mac. Mac's don't get virus's nearly as often because they have a lot less market share than PC's do but if you want to help in preventing the spreading of PC based viruses then I suggest that you run a Anti-Virus even if you just turn it on like once a week and run a scan. Also, there are viruses for Macs, but the chance of you getting one of them is very slim if you browse the internet safely and not go downloading illegal and bad programs you should be able to avoid them. Bottom line, I don't own a Mac but would highly recommended the Kaspersky brand. If you want to try them both out and see which one you prefer see these links: MacKeeper Trial, Kaspersky Trial. Try them one at a time and decide.