I'm not gonna lie, I'm definitely biased toward Intel over AMD. I have nothing against AMD, and if you're looking to keep cost down on a build, it's definitely something you should consider. I also pointed out that you could go with the Intel 1156 socket mobo/CPU over the 1155 which will shave a few hundred off the cost. Though I'm not sure how the i3 CPU will compare to the AM3+ CPUs, the i3s are all dual core (I think) compared to AMD's 4, 6 and 8 cores. It looks like at that price point, AMD would be the better choice.
Either way, AMD or Intel, it doesn't matter. The pure and simple fact remains that building your own PC will be much better than buying one from Best Buy. I don't think I can stress that enough.
@ SpaceBooger:
AMD CPU: http://www.newegg.com/Product/Product.a ... 6819103996
AMD MOBO: http://www.newegg.com/Product/Product.a ... 6813138348
With that mobo and CPU combo, you can use the same RAM, PSU, and everything else I listed above. You can even use the faster 1866 DDR3 RAM with it, slight more expensive, but maybe only $10 more for an 2x4GB kit. Anyway, that mobo/CPU is exactly half the cost ($210) of the Intel CPU/mobo combo I picked earlier. Of course, I picked the Biostar mobo this time, the Asus mobos were $180 and up.
Asus mobo: http://www.newegg.com/Product/Product.a ... 6813131736
Biostar seems like an underdog to me. The Asus name dominates, but I have a lot of love for Biostar. I have a Biostar in my i7 920 build, and I used one when I rebuilt my mom's computer. They've been great. So unless mine blows up ::knock on wood:: I highly recommend them. The Biostar board I linked has the 970 NB chipset, while the Asus has the 990FX. I'm not sure what the difference is there, since I'm not up on AMD stuff. Other than that, it looks like they have all the same features, the Asus has more ports and whatnot though.
edit: I take back what I said about the Asus boards. You can get cheaper AM3+ Asus boards, but they weren't rated as highly (that's why I missed them in my initial search).
http://www.newegg.com/Product/ProductLi ... ageSize=20
Anyway, I just wanted to do a mock build for you so you can kinda visualize it. Now we have an Intel build and an AMD build to look at. If you decide to go this route and build your own (which I really think you should) we can help you fine tune it.