Sorry, for another noob question.

Do I need an anti-virus software on a Mac running OSX? I've read a few forums, and everyone is giving contradicting views on this. I found that version 9 was prone, but OSX is supposed to be very good.

And what about a firewall? I haven't had the time to play with me missus' Powerbook, but I heard that OSX comes with a builtin firewall and is pretty good, no?