Cocktail - Mavericks Edition
Cocktail has just been updated with Mavericks compatibility. I’m not a huge advocate of OS X “cleaning” and “repairing”, but Cocktail is one of the more useful ones - and it has a great licensing model.
My most used features are quickly delete the Spotlight index, reset various OS X databases like Launch Services, and its feature to delete .DS_Store files from a tree of folders.