What is the best OS for a Quicksilver?
Depends on the CPU, GPU and other factors.
For a base model QS of any processor speed, OS X 10.4.11 Tiger is great.
For a QS of 867 MHz and up, with full RAM and an upgraded graphics card, 10.5.8 Leopard is great.
XCode 3 needs Leopard, 10.5x.
OS X, 10.6x CANNOT be run in a QS.
*Mac OS X 10.5 Leopard installation system requirements*
Leopard is no longer available at the Apple Store *but may be available by calling Apple Phone Sales @ 1-800-MY-APPLE (1-800-692-7753)*.
Installing Mac OS X 10.5 Leopard
Mac OS X 10.5 Leopard Installation and Setup Guide
After you install the base 10.5, download & install the 10.5.8 combo update at http://support.apple.com/downloads/Mac_OS_X_10_5_8_Combo_Update
Unless youve got one of the last G4's with a supported video card, or a newer flashed PC graphics card, I wouldnt bother with Leopard..
The OS will run like molasses on your G4. My last mac (which I just replaced in April) was a QS 2002 800Mhz that I upgraded with a Gigadesigns dual 1.7 cpu and also had a PC flashed Geforce FX5500 (that was BARELY supported by the core graphics stuff in Leopard) and I couldnt stand it. Leopard looked nice, but after a couple months I went back to Tiger.
It ran like butter compared to Leopard.