I went with the 500 MHz PowerBook G3 Pismo from middle school up until my senior year of high school. I loved that machine. Expansion bay (Zip, SuperDisk, dual battery options, etc.), FireWire, good looks...man, it was tough letting that one go.
I've had a PowerBook G4 (aluminum) and now the most recent MacBook Pro, and while I certainly enjoy using the more updated laptops, I don't think anything will top the Pismo.
My first was the 500 MHz PowerBook G3 Pismo. That was a beautiful machine until the display started making those discolored lines.
The next in line was an iBook G4 800 MHz, that lasted for 4 years, now the girlfriend has it.
Now I have a MackBook Pro 2.6 GHz that I bought in the late Spring of 2008.