AMD X2 4800+
Intel Core 2 Duo 2.93
I would say Intel for sure. Even though I am a AMD guy. Cheers
Do you have a quad core choice? You'll get much better results with a quad core.
I agree with Cinders, a quad core would be nice if it's an option that would work with your motherboard. If not, and your motherboard does not provide quad core support, that among the two options posted, I would say that you might get a little bit more bang for your buck if you went with the Intel Core 2 Duo 2.93!
You can get an AMD Phenom II 965 for the same price Core 2 Duo 2.93, thats the way I went, and I love that processor. This is especially advantagous if you plan on using 2 video cards, the bus stays at 4000 unlike intels which cut in half with each added video card.
Out of the two you have listed, I would probably go with the Intel. But if you plan to upgrade at all, the Intel Core i5 2500K is better then both of those CPUs, by a fairly large margin at that.
Nissanman is right. The OEM can be had for $200 also, that's lots of power for that price.
The Phenom is down to $100, but is rated nearly 50% less power. If I were building today, I would use the 2500k. I still love my Phenom, but it's a couple years old now.