Another thing that's important to do, not on a periodic basis necessarily like on Windows, but if you suspect a problem caused by file system damage, is to verify the disk with Disk Utility. If it finds problems it can fix, you'll need to boot from the Mac OS X install disc, or another bootable drive, to fix the disk. If it finds problems it cannot fix, you'll get an error such as "The underlying task reported failure on exit". In this case, a different program is needed.
I hope you don't ever have to deal with this. I have.