Windows: Partition Wizard does everything you'd probably need a partition tool to do, and does it on 32 and 64-bit systems. That alone puts it ahead of some other Windows-based partition tools. The bootable CD and simple controls are a nice bonus.
As noted by the FreewareGenius, Partition Wizard is fairly close in looks and function to EASEUS Partition Master, with the big difference being that Partition Wizard's free Home edition works on 64-bit systems, while EASEUS only offers 64-bit support in its paid editions (unless you catch one of their many free-today-only offers).
Not that Partition Wizard isn't a fine product in its own right. It handles the usual create/resize/label/delete partition operations, while also offering whole-disk fixes like Master Boot Record repair, surfaces tests, partition recovery, and whole disk wipes. It supports RAID systems, dynamic disks and disk systems larger than 2 TB, which we'd guess isn't the case for all partition software out there.
Partition Wizard is a free download for Windows systems only.