When I first installed my laptop, I already knew I was going to use Windows
for games and Linux for everything else... so I divided the harddisk in two...
30G each...
What I did not know was that I wasn't going to play that much... and that I
was going to need that unused space on the Windows partition...
Having just 3G free, I had to use Partition Magic a couple of times to do what
I wanted... it was hard and boring, but I finally made it... my Windows
partition had now less then 10G... while my Linux partition has around 50G :-)