Windows 7 taking more space than Vista?
Solution 1:
You'll find at the "Engineering Windows 7" blog a nice article describing their effort regarding Disk Space.
Solution 2:
Actually just found out what's going on.
When installing Windows 7 as an upgrade, it keeps the old OS on the hdd in the windows.old folder. This folder used up 75GB in my case.
Here's the way to get rid of this folder:
Removing windows.old folder