How much RAM does it have?
The interface and layout of the OS is inefficient. Doing even the simplest administrative tasks require too many clicks and navigation steps.
I can't agree with you more here. Setting up Windows Vista for a friend was a nightmare of never-ending friendly-looking dialog after dialog. Microsoft decided that they needed to better "protect" the users by changing around the UI instead of the underlying architecture. They should give up on backward compatibility and force apps to either move to a sane API, or run sandboxed in a compatibility layer.
4GB of DDR2. The computer came with 2gigs and I put 2 more in it when I found out he was going to be running Vista.