To perform maintenance on my Macs, I purchased a SmartDisk FireLite external FireWire drive, partitioned it into three partitions, one for Panther, one for Tiger, one for data/software installers.
After installing the OS on the two startup partitions, and upgrading to the latest version of each, I installed Alsoft's Disk Warrior (3.0.3 - Tiger compatible), Micromat's Tech Tool Pro (4.0.4 - Tiger compatible), and Coriolis Systems' iDefrag (1.1b1 - Tiger compatible) on each startup partition. Now, whenever I want to do disk maintenance, I plug in the FireWire drive, select Startup Disk in System Preferences, reboot, and proceed.
I'm retaining the Panther startup option for now because the current beta version of iDefrag running in Tiger requires Altivec in a G4 to run, but the same utility when booted in Panther works fine without Altivec on a G3. Odd, but that's how it works. The Coriolis Systems folks tell me this will be fixed in the released version. In any case, the beta works just fine on optimizing/defragging Tiger systems, preserving the Access Control Lists (ACLs) now utilized in Tiger, whether run from Panther or Tiger.
To answer an earlier question, if you have the commercial Tiger disk, it will boot all Tiger-compatible systems, including iBook G3 700MHz laptops up to the latest PowerMacs. The reinstall disk that comes with your Mac was customized for that Mac, and may not work with other Macs. It was designed to restore your Mac to its factory configuration.
For those who received new Macs with Panther pre-installed and a free Tiger-upgrade disk, that upgrade disk will NOT build a virgin Tiger drive. It requires Panther to be installed first.