O&O Defrag 12 Professional Edition ($50, 30-day free trial) is a full featured defragmentation program with many bells and whistles of varying utility, tied together with a clean interface that adheres to the latest Microsoft standards. It's available in 32-bit and 64-bit versions.
It first presents to the user a fairly typical display showing drives in one pane and the results of the latest analysis in the other, using the "colorful array of blocks" metaphor which has been standard since the days of Norton Utilities under MS-DOS 3.0. O&O Defrag 12 foregoes the standard menu bar in favor of the new standard "ribbon", a là Office 2007, and manages to use this interface in an intuitive and productive manner. The various tabs and control groupings are logical, and there were few times I ever had to ponder where to find a particular feature. If anything, the strict adherence to interface guidelines almost becomes comical; how often will you need to adjust your defragmentation utility's color theme? If you want to, though, you can.
On the more functional side, O&O Defrag Professional offers a feature found in most modern disk defragmentation utilities, the ability to designate zones on your disk. You can place frequently accessed files where they will be found the fastest on your hard disk, and infrequently accessed files in the slow outer reaches--though when you consider current hard disk speeds and various OS-level optimizations, the speed difference for an average user is likely to be small. You can also choose to have O&O Defrag arrange unused space so as to create the largest possible block; this is useful in controlling future fragmentation.
O&O Defrag provides a great deal of information about your disk besides mere "%age fragmented." The reports include which files were moved, which were the most fragmented, and so on. This data is of relatively low use to most home users, but can be quite important to someone doing network administration.
At $50, O&O Defrag Professional is at the high end for a utility program whose main function is performed--for the purposes of many--well enough by a free tool included with Windows. In terms of "competing with free," O&O Defrag Professional comes off very well. For instance: MyDefrag, a powerful free utility, is hindered by a script-driven interface which subtracts more in ease of use than it adds in power. When O&O Defrag Professional competes with other commercial programs, it offers a bit less for a bit more. Perfect Disk Professional, for example, includes a duplicate file finder and boot-time defragmentation. Since both commercial programs provide free trials, it might be worth your while to see if features or ease-of-use issues make O&O Defrag Professional worth the extra money.