Chessbase's nearest competitor is the Convekta Chess Assistant ... though Convekta programmers (who, in their previous bastardized births were vikings who pillaged villages and conducted violent orgies aboard longships that happened to be on fire at the same time) design interfaces/GUIs that do a great job of thinning the herd of non-serious chess players, who kill themselves within weeks of figuring their way around the software. => I believe this might be an acquired taste.
SCID (the free open-source database application) does a lot of things really well ... though most of the games/databases out there require some conversion (native, PGN etc.) before you can get started. Also seen more bugs and crashes here per time spent than in chessbase. Still a great (and free) way to work with databases.
I am in the market for a good chess database program. I have worked with Chessbase in the past and really thought it was a good program, but I am wondering if anybody out there has any other suggestions. What programs do you use to study chess, and how do they stack up?