The Abit NF7-S & the Asus deluxe are 2 of the best especially feature wise. They both run neck and neck speed wise, not that there is a huge gap between any one board in the speed department. Just be sure to get the 2.0s or I think it's also called C stepping revisions of the nForce2 boards.
I saw a Gigabyte board the other day that let you use 4 RAM sticks in dual channel, never used that brand before though. I belive those are the Ultra nForce2 boards.