Supported virus software for 10.7

I suggest you read these forums for the terms "mac anti-virus"

the overwhelming findings so far is none have ever been faced with an actual mac virus nor shown they are capable of much more than crashing, panics and false positives when they are not interfering with the OS. Most, if not all Mac Anti Virus products have far more wrong with them than any benefit whatsoever to mac users or mac users who use it to protect PC's or network. The finding here so far, they don't help, they hinder.

the answer to your question is the single best practice for protecting Mac OS is to keep your system up-to-date with securities patches and OS updates from Apple.