There have been some problems with the IBM 60GXP hard drives. I've got one but I've never had any problems with it though. YMMV

You may have trouble using 120+GB drives with your old BIOS. Some larger drives come with a new controller card that supports much bigger drives.

If you can, you should really reinstall from scratch. You'll be amazed at the speed up from just reinstalling Windows. It tends to collect crap from installing/uninstalling applications and just general use.

- Trevor