I went with a Western Digital Scorpio Blue 320GB drive.
It formatted OK, using the Windas XP set-up disk, then proceded to give me a blank screen and the message:A read error has occured, press CTRL, ALT + Delete to re-start.
Re-starting, gives the same thing.
This is a Windas fault, nothing to do with the drive.
The BIOS recognises the drive as 137GB, but that can be changed after the OS is loaded on it.
It would be nice to actually get the OS onto the disk.
I googled that fault message and apparently I'm not the only one having this problem.
There are screeds of people that have bought new hard drives, but can't install them because of a fault in the OS and what makes it worse, M$ isn't doing anything about it.
They merely say "upgrade" to Vista or W7, which most of the software on my lap-top will NOT work with.