Buy it online if at all possible, that way you know what you are getting.

That being said, some stores may be so desperate to make a sale that they will give you a great deal, just make sure that if they give you 25% off of a $2000 laptop, that it was a $2000 to begin with, and not a $1500 laptop that they listed as $2000 so that they could call $1500 "25%" off. I used to work for *Insert major computer retail chain here* and they would do that all the time.

Many laptops still only come with 5400 RPM drives and that's a major bottleneck so try to find one with atleast 7200RMP.

You will also want plenty of RAM, especially since this thing will be running Vista. I'd generally recoment 4GB which shouldn't be too expensive. Pay attention to graphics cards in laptops. They will try to pass an crappy integrated graphics card off as something cool. They have mobile versions of Geforce 9800's. Get one.

The CPU is an interesting thing: people, when getting a performance laptop, people are inclined to get the fastes CPU possible but that is not always the best idea since if the rest of the laptop is crappy, its like having a nice V8 in geo metro. Theoretically it could go fast, but its still a geo Metro. It its duel core get >2.0Ghz if its over that >1.7Ghz. Faster is better of course, but make sure your GPU and RAM are upgraded first before using whats left of your budget to upgrade the CPU.

As far as from whom: I'd personally go with Dell, though HP isn't bad normally. I have had some problems with HP laptops, but from talking to other people, it seams to be just me that this has happened to.