Whats using your hard drive space?
When I recieved my new laptop with it's non-fill-up-able 60GB hard drive, I thought I was sorted... 6 months down the line I've used 50GB of it
After some searching on Google, I found this Hard Drive Profiler. It scans your hard drive, and ranks folders by size, and also provides a pretty pie chart. You can drill down to see what makes up a particular folder too.
It wasn't too much of a surprise to find out that c:\downloads\videos\ is hogging most of my space :-)