How big?

how big should i make my partitions? how many should i make?
Should i use Partitions on a raid0??? (its single ide channle raid0)

do partions slow my pc down?
I have 2x80gb so i have about 160gb.

its just i heard it slows down ur pc but is safer.... but in raid partionswould be pointless right cuz if one HD goes both of them are curupted.

so what should i do?

for get it i found out what i wanted to know
i set a 30gb partion for apps and windows

check this out - http://partition.radified.com/

I have 2 80gb drives, 3 partitions on each drive.

Windows on a 15 gb partition- makes a wipe/install safe, protecting data on the other partitions.