I use PhotoImpact X3 because I can manage and edit my photos within one program.
Also, it is able to edit the RAW image types I use ( Fuji .RAF , and Kodak .KDC ).
The Kodak .KDC format seems to be a bit of a neglected odd duck, which many photo org. programs can't open. (ie ACDsee pro : from the p-880 camera - yes, from the p-850 camera - no. go figure!).
Also PhotoImpact X3 gives you the option of saving your photos to 48 bit. Not that I often (ever?) use that option, but it is there if you want it.