Now that PartionMagic seems to have died, I was wondering, what do you guys think is the best Partition Software?
GNU Parted. Or if you want a nice GUI, GParted. A live/bootable CD image is available from the GParted folks. I've used these products many, many times in the past to create/extend/shrink/etc partitions both in Windows and linux systems, and have never had issues with data corruption. Usual caveats apply, though, for partition resize operations.