Desktops: Ideal PC for a website/graphic/video designer???

Actually...

Video card isn't that important. Just get one that supports dual output (try for dual DVI) and DirectX 9 support. Most things for the types of apps you use are handled with CPU and RAM. Games, AutoCAD, and 3D modeling apps are the programs that really utilize video cards. Some aspects of Photoshop can use them, as well as some video editing programs, but they don't really tax the card very much. Windows Vista will probably be the most taxing thing that video card will ever run. So don't spend more than about $100-200 on the card. Something in the range of a GeForce 7600GS or ATI Radeon x1600Pro card should do very well for that price range.

For the rest of it, dual core would be good. It sounds like you will be using several processor-intensive applications at a time, so they would definatley benefit from dual-core. If you are getting it right now, I would opt for the new AM2 socket AMD 64 X2 processors(assuming this is a custom build, otherwise, just any old AMD64 X2 will work, try for at leas 3500+, whatever is the best bang for the buck), they currently lead Intel by a decent margin, performance-wise. If you are waiting a bit, see how the new Conroe core processors from Intel benchmark, they look promising.

For RAM, 2 gigs would be a very comfortable point to be at, if you think you will do a lot of video editing, then consider 4.

For hard drives, the bigger the better. The only thing to note here is if video editing will be a significant use of the machine, you may want to opt for one high speed drive like a Western Digital Raptor.

Other than that, everything should be pretty much built into the motherboard...NIC, Sound, etc. For monitors, Samsung seem to be good bang for the buck, Viewsonics, too. For art work, look for a higher contrast ratio (500:1 and higher), and always at most a 12ms response time, 8 is very standard now though.