Ok, some not bad choices, here's what I'd get for $1000.
Keep in mind I'm human and tend to get a bit of brand loyalty, so someone else could give a good suggestion for something instead.
Case - X-Plorer
I like the case, it seems to be a good budget case.
PSU - ePower Puma 450watt
This is where I'm not to good, I think it's the cheapest I could find from a good brand... someone else should give you a suggestion.
Mobo- Abit K8N SLi
I don't think you'll do much OC'ing, and it's sopposed to be a good stable board, it's got the good standard nForce 4 features and sli.
OCZ 1GB stick RAM
I'd suggest a minimum of 1gb, I nly buy OCZ or Corsair ram, I find it's great quality, even the value ram from them.
Seagate SATAII (3.0) 160GBHD
Once again I only buy Seagate, but most other brands are fine I guess.
Optical- NEC DVD Burner
Burns DVD's..only $40 great deal.
Here's where it get's into what you want... all that comes to about $500... so you could buy a $300 dual core AMD 3800 x2 and a $200 6800GS (this would allow you to buy another later on for SLi if you wanted). Or you could buy a $200 Athalon64 and then a 7800GT.
If your not doing any major GFX work then I guess it'd be okay to go with a regular processor and get the power w/ the 7800GT, but I's suggest scrounging up $100 and nabing a 3800 x2 and a 7800GT
Here's a list of the processors/GFX cards I'm talking about.
This is the $200 athlon I was talking about
A64 x2 3800
This is the dual core I was talking about
Ok, here's the GFX cards, a lot of people like eVGA so I'll just give you the link of the eVGA 6800GS, some brands are better, but quite a few are worse.
Here's links for the 7800GT. I'm getting either the XFX one, or the Gigabyte one.
Hope that helps... on another note, I just saw the ASUS 7800DUAL card for $900 on newegg... crazy.