Yeah I'm thinking about those new ATi mainboards also. I was thinking of getting an Audigy 2, but if that hardware audio is decent, I'll stick with it.
To answer the questions...
1. Primary uses for my computer are workstation apps (3dSM, Maya, Photoshop, CAD, etc.) and gaming. I don't want to have to sacrifice either of those, so the dual-core was my best solution. I've seen multiple people get their 4400+ up past 4800+ levels, and have even seen a few hit 2.6GHz. Dual FX-55 processors will be good enough for me.
2. Yeah I'm waiting till Christmas-time, since there are always huge price drops and sales. That's also part of why I put the 4400+ as the part to get. I'm thinking it'll be in the low-$500 range by then, and the 7800GTX might be in the mid-$400 range. I'm going straight to the 7800GTX because I don't want to have to upgrade this computer for as long as possible. Sure, it can run today's games at 16x12, but who knows what will happen in the coming years? If the Xbox 360 and PS3 have shown us anything, it's that graphical advances will port to the PC quite quickly.
3. Since one of my main concerns is gaming, the prospect of a 4ms LCD seems quite enticing, seeing as CRTs perform as 4ms as well. And while I have the desk space, it would be nice to be able to keep the subwoofer behind the monitor instead of on the floor. And, I'm trying to head towards a minimalistic look as well. The Dell LCDs are quite expensive at this point, and I can't seem to find any specs for them. From what I know, they have 12ms response time and not sure if they have DVI.