I've been using LogTen Pro for over 2 years now. True, in the beginning the software may have been a bit buggy but since those flaws were taken out of the program it works great! The developer is very active in getting and using feedback in LogTen and the support is just awesome!

If you already have an electronic logbook (from excel sheet to anything you can export to comma-seperated text) you can very easily import it into LogTen.

LogTen is the best logbook program I've seen so far, that's including applications for PC. The price may seem a bit steep but everyone who knows what it's like to maintain a paper logbook knows that it's so much better if you don't have to worry about a cramped hand after 3 months of NOT writing your flights down and making tons and tons of mistakes in calculating your times...

With LogTen Mobile 2.0 for the iPhone coming up things just keep getting better :-)