I'd recommend going for dell - my customer support experience with them wasn't great (my order got delayed a week, and then they shipped it ground instead of next day air, which they had promised - on the other hand, they did give me enough credit in their online store for me to buy a nice case, computer fan, and an extra USB flash drive), but I was very happy with what I got.
I would suggest going into the business line of computers (I got a vostro). They're cheaper, and they come with less junk programs. Also, if you want an extended warranty, you can get one for less than half the price (I think their full 3-year warranty was something like $130, compared to the usual $300). And I got the specs I wanted, when I would have paid about $400 more from any other company.