I'd recommend a Lenovo Thinkpad T series if you plan to keep it for a few years and lug it around a lot. Thinkpads have legendary reliability and build quality, plus features like spill proof keyboards and full magnesium alloy internal rollcages that you won't find in many other laptops today.
The T61s are heavily discounted right now because the newer T400s just came out, but the two models are similar performance-wise. The T400 adds hybrid graphics (integrated AND discrete graphics that you can switch on the go depending on what you are doing) and an LED backlit screen, among other cool features. The processor, GPU, and other performance are similar to the older T61 though.
I've taken my T61 to LAN parties and it plays Counter Strike Source and TF2 well, especially with the GPU a bit overclocked in Rivatuner. The NVS 140M is a crazy overclocker in mine, and with it stably OC'd to 8600GS levels I can play CS:S at 1440x900 with AA on and high details. Even at stock it's capable of playing CS at 1280x800 without a problem.