I installed Leopard on my old PBG4 last weekend. I did a clean install and am slowly moving over prefs and files (iPhoto and iTunes moved over.) In general I like Leopard and it runs fast on my old 1 Ghz machine. There’s things I don’t like (the 3D dock, the transparent menu bar) but I know that the internal updates are worth the update.
What I cannot comprehend is how Apple could have not implemented Spaces with the ability to have separate desktop images. What’s the use of virtual desktops if you can’t change the desktop images so you can have a visual reminder of which desktop you are on? It’s absolutely incomprehensible to me that I have to have the same desktop image on all of my “Spaces.”