Don't partition your drives. Partitioning is sort of a silly idea, and while it can be useful if you only have one hard drive and want two operating systems, overall it does not provide any real benefits. I love it when I see people who "backup" their hard drive ON THE SAME HARD DRIVE on another partition. Well if the drive fails, you lose both anyway!
I also don't think partitioned drives defragment as well. I keep my computer extremely streamlines with no weird crap like partitioning. get an external hard drive or a second internal to make life much easier.