Go for the AMD man.
And just take the extra time to build it, its soooo easy, takes no time at all, and you save so much cash. Its just another skill to have under your belt that saves you huge amounts of $$.
If you dont want to buld it.. i guess go for a dell, they seem like the best value.
In all honesty that comp you posted above is junk, you can have a puter equivlent to a higher end alienware for 1200 easy if you buy the components off of tigerdirect and just put it together, even if you pay to have it put together you could have a much better comp than that.