The NF7-S is your best bet. It's fast ,stable, and the onboard Soundstorm audio is awsome. It's the one I have.
NF7 - No Dolby Digital 5.1 Soundstorm surround sound.
NF7-M - No Soundstorm but it has GeForce4 MX onboard video.
Here's a comparison chart from
Abit.