depending on how extreme you are using the computer, i would still recommend an intel celeron. They are very cheap, and the new processors are going up to 3.3 Ghz.
before considering any computer purchase, memory is the #1 consideration. Always put at least 512 MB on your PC, no question.
also, make sure you have a decent sized hard drive. i recommend at least 80 gigs, as videos take alot of room, as well as photoshop.
another thing to consider is a video card. Just make sure you are not using the integrated video on the motherboard, it doesnt work good at all.