how big is the HDD installation for knoppix 3.3?

[Jiros]

I was wondering, I have lots of harddisks but I want to choose wich, so does anyone know of you how much space it cost?

[Markus]

Uncompressed I think the CD holds about 2.3 GB, so a minimum for an install would be 2,5 GB if you plan to clean it up a bit and don't plan on installing lots of new software.
I would set it up as follows:
4-5 GB for /
2*RAM for swap (max 1 GB)
100MB - ?GB for /home depending on what you plan on storing there.
2 GB FAT formatted partition for moving stuff between Windows and Linux.