Check out VersionTracker for the Mac:
http://www.versiontracker.com/macosx/
Not only do they have utilities, but games, antivirus, network, internet, and more. Some is free, some is shareware.
Diskwarrior by Alsoft:
http://www.alsoft.com/DiskWarrior/
I have found it an essential tool for Mac disk repair, in addition to Disk Utility that comes with the Mac (under Applications > Utilities)
And I'd never be without Cocktail. No, not the beverages. It's a fantastic general purpose utility for cleaning up Mac OSX. But ya gotta pay for it. At only about $15 dollars it's worth it.
http://www.maintain.se/cocktail/index.php