I've found that OSX really keeps itself pretty clean anyway, but have DiskWarrior on hand just in case. Remember to repair permissions every once in a while (Applications/Utilities/Disk Utilities) and I run a program called MacJanitor every once in a while (
http://www.versiontracker.com/dyn/moreinfo/mac/10491 ). Mac Janitor performs three vital system clean up tasks that would normally be performed early in the morning automatically on a system that is run 24/7.