The last time I took a look a TeraCopy Pro ($20, limited demo) I loved it, but it crashed during one copy test. It didn't take any data with it, however, for a task as critical as copying and moving files failure is not an option. Thankfully, this more recent 2.1 version of the program performs as happily and accurately as a trained seal.
TeraCopy replaces the Windows file handling functions with its own, which appear on the right-click context menu or simply when you copy or move files. The pause function alone is worth its weight in gold if you do a lot of copying. Windows only lets you cancel--not pause--which makes it difficult to ascertain exactly where you left off. You may also choose up front whether you want to overwrite all files, older ones only, skip files that already exist, or rename the file being copied to avoid overwriting the existing files. Vista and Windows 7 provide the same choices, but only when the conflicts occur after the copy process has begun. Anyone who's ever started a large copy operation, gone to lunch, and come back to discover that Windows is only two files into the process and wants attention can appreciate Code Sector's approach.
You may also invoke TeraCopy Pro as a standalone so you can select files from diverse locations and copy them to a single location. You may also create favorite destinations to cut down on your browsing time to them. Checksums are generated for verification--a great safeguard, especially when you're copying files to less-reliable removable media.
TeraCopy Pro adds a few very handy perqs lacking in the free TeraCopy Home: letting you select all files with the same extension, and letting you remove files from the copy queue. It includes free updates (though it seems you get those with the free version as well). Without a help file it took me a few minutes to realize that the selection options apply only to files already added to the queue and that it didn't gather more files from a location.
All told, TeraCopy Pro is a nice replacement for Windows' reliable, but singularly under-powered, copying and moving routines. As I said earlier, if you do a lot of copying, it's worth it, though it might be more worth it at $10.