I'm with Paddy...
Panther is capable of taking care of itself for the most part. Repairing permissions after a new install or if any flakiness is detected will take care of most all problems you will encounter.
If you experience bigger problems, you have Disk Repair which can be run from the Panther installer disk. The system has to be pretty messed up before running fsck is a necessity.
I keep a copy of DiskWarrior and Drive 10 handy, but the only third party utility I use regularly is Cocktail to force the system to run cron scripts once a week.