My old computer is going and I'm pretty set on a Dell 8300. This is the deal I found on techbargains for a Dell XPS 8300 Intel Core i7-2600 2.4GHz Quad-Core Sandy Bridge Desktop 24in LCD $929
And here are the graphic card options:
NVIDIA GT420 1GB DDR3 [Included in Price]
ATI Radeon HD 5670 1GB GDDR5 [Add $20.00 or $1.00/month1]
Single AMD Radeon™ HD 6870 [Add $280.00 or $9.00/month1]
AMD Radeon™ HD 6770 [Add $80.00 or $3.00/month1]
Nvidia® Geforce® GT530 Add $0.00
Quite frankly, I don't know where to start. I'm a writer, so I use my desktop primarily for that. I write comic books, so there is a fair amount of viewing art files, although I don't tinker with them much so I doubt that would tax a GPU very much. But I'm a gamer as well, and would love to be able to play Civilization V, and the upcoming Star Wars The Old Republic MMORPG, and probably a bunch of other games I'm forgetting.
I don't know what the difference between the GT420 and GT530 are if they are the same price. I wouldn't mind spending $20 more for the HD 5670, or $80 more for HD 6770. $280 for the HD 6880 seems rather steep though, especially I'm trying to keep the price at or around $1000.
The graphics card is the most important part of the system when it comes to gaming. I would say go for the 6870. The 530 and 420 will both give really unacceptable gaming performance, so stay away from those.
The 5670, 6770, and 6870 normally retail for roughly $80, $130, and $200 respectively. Their relative performance roughly corresponds to their relative price. Your best bet might be to buy your own 6870 instead of getting it from dell, since it would be cheaper that way, though im not sure how that would affect the warranty.