I'd choose XP over Win2k. You'll have enough RAM for the additional bloatware that comes with XP and I've had fewer problems with XP than with 2k.
FWIW, I've never had any serious problem with 2k. The best argument for XP I've heard is ClearType, which is supposed to make the text easier to read on the screen. I may try XP just for something new.
IBM uses a hidden partition for their Recovery button, as you may be aware, that recovers the whole system to the factory setting at the touch of a button. Some people prefer the extra space rather than having a ready-to-go recovery system, others prefer the convenience of the recovery system.
The current recovery software reads very well
http://www.pc.ibm.com/us/think/think....html?re=pcdtv
http://www-307.ibm.com/pc/support/si...GR-4Q2QAK.html
I thought that the IBM X31 used 1.8inch drives, not the 2.5inch drives. Am I incorrect? because to my knowledge, there are no 60GB/7200rpm drives for 1.8inch yet... and if that's the case, your 60GB will not fit in the laptop.
You're thinking of the new x40 model, which uses the 1.8" drives. The ability to use a 60gb/7200rpm drive was a major reason for going with the x31 over the x40