Processor: I would recommend Intel over AMD these days with the Core 2 Duo, although the Athlon 64 X2s aren't bad. This is the main decision, IMO, in building a computer. You might not need a dual core CPU now, but I'd recommend it just to help your computer stay somewhat recent and up-to-date in the future. You are in the US, so you can purchase components right from
Newegg.com. You can look at a few Intel Core 2 Duo CPUs
here arranged from cheapest to most expensive. The Core 2 Duo is currently the best performance CPU in the mainstream market. Core 2 Extremes are better, but are overkill for what you will be doing. For video work, I would strongly recommend a Core 2 Duo if it is in your budget.
Here are Newegg's AMD Athlon 64 X2s.
You can compare CPUs
here.
One thing you didn't mention is a budget. If you cannot afford the somewhat expensive dual cores, there are cheaper options that will do pretty well, such as AMD's Athlon 64 CPUs.
RAM Quantity - for Photoshop CS I would recommend a minimum of 1 GB and would recommend at least 2 GB if you can afford it. The type and speed will depend on the motherboard.
Graphics - you probably don't need the latest graphics card, but I would recommend getting one with 256 MB or more of RAM onboard. What type of monitor are you using? Some cards today only have DVI out, although there are adapters. For the interface, you will almost definitely want to go with PCI Express 16 since that is the most recent. The motherboards for the modern CPUs should have at least one or two buses/slots. This might be hard to pick an exact one until you know a few more components and have a price range. But, you can see Newegg's cards
here and another useful comparison
here of models.
Hard drive and Backup options - I know from experience that photo and video editing take a lot of storage, so I would recommend at least 320 GB of storage if it is in your price range. You'll probably have a better estimate of what you will need based on what you currently have. You may want to consider an external hard drive for nightly backups. There are now cheaper network attached storage (NAS) devices that backup over your network and can backup multiple PCs, although they are still expensive.
Motherboard - this really depends on the processor you pick and the budget.
Edited by Pi rules, 14 June 2007 - 03:01 PM.