When many Windows users switch to the Mac, one of the seemingly logical features that is missing is the ability to cut and paste items in the filesystem browser. Many people get used to this for organizing their files, and to see it missing on the Mac takes a little getting used to if you have frequently used this feature.
While OS X supports file copying and pasting by selecting the file and pressing Command-C, followed by Command-V after bringing the destination window into focus, the ability to use Command-X to "cut" and essentially move the file to the new location will not work.
There is a small utility, called MoveAddict, that, like its name suggests, will appeal to those who have found the ability to cut and paste files to be invaluable, or at least somewhat useful.
The program is a small $5 utility that adds a new menubar to the system, and when browsing through the Finder you can now make use of Command-X for moving files. Beyond cutting and pasting files, the program also allows you to merge folders instead of replacing one with the same name if it exists in the destination folder.
Unfortunately if you are using Leopard or are on a PowerPC Mac you will not be able to use this program since it requires Snow Leopard. However, this did not prevent me from at least trying in a ditch hope I could bring this functionality to my G5 (they're correct, it doesn't work).