Well, I buy a new computer of some type every 4-6 months so I think I can give you some opinion
If you're in the laptop market, I'd recommend a Sony Vaio, a Dell Latitude, or a Apple Powerbook - depending on your preferences.
I have two iterations of the Sony Vaio here in the house - both of them are the PCG-505 superslim models w/ docking stations - running WinXP - they rock. About 3-4 lbs, lots of power.. no complaints.
If you're an Apple fan, then I'd recommend the PowerBook G4 15" laptop - I have one of these and use it as my primary computer.
If you're looking for a desktop, I'd recommend a Dell, a Gateway.. or if you're comfortable with Macs, get a PowerMac G4 or G5.
I have a Dell p3-933mhz box that I use for gaming - it's more than two years old but can run anything on the market, never had an issue, love it.
My primary desktop is a PowerMac G4 that's a year old - Dual 1.2ghz processors, 2GB of RAM, and a 23" LCD.. it rocks.
Hope this helps

Bryan