Well, the first place I'd keep an eye on is the Hot Deals page.....
Also, I'd keep an eye on the various retailers specials (Staples. Officemax, Office Depot, etc,etc) Usually at least one has a laptop on special
Still a few things you'll need to consider-remember that in most cases you have to live with your decisions- usually upgrading a notebook is either impossible, or very expensive. Also, take a long hard look at the makers warrenty, and repair policys. If possible- take a look at the screen before you buy- look for dead Pixels, etc,etc
How much traveling do you do? If its a lot- definately look at battery life- obviously longer is better. Also- I'd personally check out the price for a spare battery- seems like the things will die on ya at the worst possible moment- as in you've got work to do, and no plug in handy!
Look for as many features as possible- Personally, wouldn't get anything without a DVD read/ CD writer, built in wireless (preferably 802.11g), and at least a 14" screen.
Also- remember to save some bucks for additonal items- briefcase, upgrading the Memory- possibly a small mouse, etc, etc
Persoanlly, I've been very happy with my HP/Compaq NC6000 - 3 1/2 -4 hrs battery life, decent processor speed (1.8 Pentium M), fairly good size HD (40gb), and upgraded the Memory to 1 gig