EPKPHOTO  Ever since it began supporting syncing computers across "remote" networks, MySync has been growing up nicely. Recently, strong security has been implemented and the app is very stable. If you have a need to do some basic syncing of Address Book, Mail, iCal, Safari bookmarks, Keychains, or even Entourage Notes, and you don't have/want .Mac, give MySync a try. Keep in mind that it is still beta, though.  
(Version 0.74b)

EPKPHOTO  I've been running Azureus for nearly a year now, and I have not had any problems double clicking a .torrent file to open it in Azureus or problems with the dock icon. Once I set Azureus as the default application for .torrent files in the Finder's Get Info dialog, the file association has stuck.

I'll agree with others that Azureus can be a resource hog, but if you weed out the torrents you are seeding occasionally and don't try to download too many torrents at once, it runs great on my dual 800Mhz PowerMac G4.  
(Version 2.4)