A couple of ideas for you. Over the last 10 years I’ve used or maintained (I do IT for a small company) Dells, Acers, Sonys, HPs (and Compaqs before that) and Toshibas. The Sonys and HP’s were the least reliable but I’ve been told by others in the IT business that HP has greatly improved recently.
If you’re going to be lugging it around a lot, or even sitting it on your lap, consider going with the smaller screen (usually 14.1″). The extra weight really does make a difference. If you’ll be using it mostly sitting at a desk, the larger (usually 15.4″) is fine.
If you’re not going to go Mac, there really is no reason to spend more than $500-600. My favorites right now are the Dell Vostro line and Toshiba satellites.
The dell vostro line was specifically designed for business users and doesn’t come with all the pre-loaded crap that most people never use anyway. They’re a bit heavy but very sturdy and reliable. I’ve got 3 of them in my office. As of a few days ago, they could also be loaded with XP instead of Vista at no additional charge. My experience with Dell’s service department has also been very good.
The Toshiba satellite line gives great bang for the buck. The Best Buy Black Friday special (model L305D-S5892) was like $379 but not available anymore at that price in retail outlets, but is still available on ebay in the high $400’s. I bought 2 of them, one of them for my personal home use, and its working fine. My only complaint is that they’re a bit heavy. Of the older Toshibas that I’ve had, I’ve only needed service on 1 (out of 3), and their warranty service was outstanding. Call them up, give them the serial number and they tell you where to take it to get it fixed, no hassles whatsoever.