NOD32 is definitely a nice AV. But for firewall...I don't have Vista (nor do I intend to install it), so for that you can try the included Windows firewall (ugh! never expected to give out that advice to anyone

) until CF version 3 is finalized. I only "recommend" that because I assume the Vista firewall is built into the OS just like the XP firewall, so resources should be lighter than almost any other 3rd party firewall. Be aware that by default it doesn't turn on outbound protection (at least from what I've read so far).