Even though the computer was already obsolete in 2009 (I used a 2006 Core Duo MacBook as my daily driver, which ran circles around the old Power Mac G4), it was a capable machine that could run Mac OS X Leopard and could handle the Web of that era, even YouTube videos. Eventually, sometime around 2013 the Web became too much for my Power Mac G4, but it remains a very nice machine for Mac OS 9 and early Mac OS X retrocomputing. I now have faster PowerPC Macs in my collection (a 1GHz PowerBook G4 and a 1.25GHz Mac Mini G4), but my Power Mac G4 is the fastest machine in my collection that could run the classic Mac OS without any modifications, and it is also the fastest Mac in my collection that has expansion slots.
I'm keeping an eye on 2019 Mac Pro prices (I own a 2013 Mac Pro, which I purchased refurbished in 2017 and used as my daily driver until 2022, when I switched to a Ryzen 3900 build). I love the aesthetic, but they're pricey since they are still quite capable Macs despite the transition to ARM. Once they drop to under $500, I plan to buy one and add it to my collection.
Update: I found my old blog post about my Power Mac G4: https://mmcthrow-musings.blogspot.com/2009/04/new-power-mac-...