Can't go wrong with an 8800. DX10 is not a requirment. It's marketing BS to force you to buy Vista, and will only really matter for Games. Most 3D rendering and modeling program use OpenGL and the 8800 has is great OGL performer... unless you're using Vista ironically, because Vista has decided to force all OGL calls through DX10 weather you like it or not. If you're going to be using this machine as a general all purpose Web/Email/Word Processing, machine that also does kick ass graphics, stick with XP Pro 32 for now. It's got the best drivers and to spite M$ BS, is still the best supported. Dale B is right about the sound cards, but you won't easily find a motherboard these days that doesn't have built in sound, and again... if you intend to play a DVD, listen to an MP3, or EDIT VIDEO with audio on this machine, your only other option is a high end $300+ sound card that will take the audio loads off the CPU. Of course at that price your 1/4 of the way to a second PC. This is a good reason for a Quad Core though. If you can afford it those extra processors will do the work of that expensive sound card with the built in hardware, and still leave you 3 cores to get the rendering job done.

mo·nop·o·ly  [muh-nop-uh-lee]
noun, plural mo·nop·o·lies.
1. exclusive control of a commodity or service in a particular market,
or a control that makes possible the manipulation of prices