good point with the wireless card, but 99.999% of all new laptops you buy should have an internal wireless card. I've never heard of one sold without one now a days.
I completly agree with IBP's recommendations. I haven't done any 'puter shooping lately, so I'm not really up on the current stats, but as a former IT guy myself, I can confirm he's nailed all of the important general stuff.
One thing I will add is if you are looking toward a laptop, be sure that you get a wireless card with it. Most should have it included, but be sure to check. You'll want to be able to use it around town, and there are getting to be quite a lot of places that offer free wireless access nowadays.
And always be sure to make backups of your hard drive!
You might consider some sort of external storage for this.