Diskeeper Home Edition 8.0 is one of the best defragmentizer you can find for Windows (even better than NortonSpeed Disk, but even more expensive, 41$ for ONE application) . It is fast, and can defragmentize your HD without restarting or stopping other tasks (this is its main feature), and is very easy to use. Good.

There is a little I can say on PartitionMagic 8.0 , since I consider it the best application for Windows. PartitionMagic 8.0 allows you to create, resize and merge partitions on your hard drive without destroying data, helps organize and protect your data, run multiple operating systems (Win98, XP, WinMe, Lynux...), convert file system types and fix partition table errors. It is like doubling or trebling your pc. You can -for example- create a 'test' partition to try and test all the software you download from the Web (a partition you can easily reformat, in case of disaster) and a 'safe' partition where you can use all your 'important' software (like Word, Excel, etc.).

Another good app for partitioning is Paragon Partition Manager, almost on the same level of PowerQuest Partition Magic.. still a great value. You can create, resize, convert (FAT<->FAT32<->NTFS) partition, and even use the Master File Table defragmenter, a built in utility for defragmenting the core of the NTFS partitions, increasing the performance of the system, support of USB disks.

 OVERALL: Good (Diskeeper), Excellent (Partition Magic and Paragon Partition Manager)