http://

or, if you can make an extra $500 appear into the equation:
http://

If you're a student or you know a student that can buy one for you, they have student discounts:
http://store.apple.com/Catalog/US/Images/routingpage.html

OR... if you dont want a mac, (OMG WHO WOULDNT WANT A MAC) id recommend choosing a site that lets you piece it together part by part, i cant think of one off the top of my head but i know there are some good sites out there with good deals. ill find a few and post them later on when im not at work

EDIT: http://www.cyberpowerpc.com/?gclid=COrY9vbO5ooCFRlmWAodFRECpw

this site has some really nice deals, plus you can choose from a few "free gifts"

i don't know what other purposes you may want the laptop for, but these should be more than enough power to run any of the apps you might be using.

then again im pretty new to the whole recording side of things so maybe someone else has a suggestion of a more 'specialized' selection. All i really know is those are some good deals on some pretty powerful machines. Also check out http://www.newegg.com they are always running new deals and have incredible service.

ALL in all i guess i didnt help very much with the choosing, but those are some good places to buy.

id stay away from major retailers (bestbuy/compusa)
they charge too much

and major brands (HP/SONY)
they also cost more than the parts they put in them, and they put a bunch of software that really just slows down your performance in the end.

EDIT2:

Oh and make sure to get windows XP. stay away from vista for now when it comes to a DAW. much of the software out there is less than "compatible" with Vista.

If you have to use Cubase, the only version that will work on a MacIntel is cubase4.

Also cubase4 on a MacIntel Is F**ked up situation, bundled plugs that were done by Wizoo will never be ported because Digidesign now owns them.
Plus they changed the VST standard, so none of the MacIntel plugs work.

So if you really want to use Cubase4 stay on PC, people have been booting to XP to use SX3.

I use Logic Pro on a Core Duo Mac Mini.

8)