I am pretty happy with the Dells that my company supplies. I would recommend a 600M or a D600 if you want a built in optical disc or a D400 if you want a smaller machine for travel that does not have a built in CD or DVD player.

Definitely get a computer with a Pentium-M chip if you can afford it. Although they have slower clock speeds than the Pentium 4, they actually perform better.

One very good option if you are tough on equipment is complete care, where you are covered for your own accidents such as coffee spills and equipment drops.

If you want an older machine, Dell Financial Services sells 2 year old lease returns on ebay for $500-1000. I purchased one of these for home use and it looks like new. It even came with one year left on the complete care warranty.