ThinkPads are good laptops, but as stated, the T42 is a bit dated.
I got a T40 with a Penitum M @ 1.5GHz from 2003 and it's pretty difficult to multi-task with it compared to modern laptops / PCs. It still works fine, but the battery only lasts 2.5 hours now.
I can play some old DX8 games on it.