1) Wasn't it the A7N8X Deluxe that had 2 LANs?
2) Yeah, the thing rocks, but the three dimm sockets suck. However, most nforce 2 mobos have that problem.
3) The newer versions of the A7N8X also sport the Nforce 2 400 chips.
4) Most new motherboards have onboard 5.1 soundcards, so don't go buying this mobo just for that. Also buy it because it's just a great board.

5) downside: only the deluxe has Serial ATA, which is getting more and more popular. If possible, get a board that has a SATA option; you'll need it in about a year, when most harddisks will be SATA. (Oh, and the Western Digital Raptor SATA disk is also a good reason to get such a controller...)