This is not a tip... as much as it is praise.
Having used Leopard for a few months now, I have absolute confidence in it as a stable platform for running ProTools. I am running both an LE system as well as a HD system (both Leopard). One of the new Leopard features that I do love is screen sharing. Because I work in ProTools HD all day on a Mac Pro, my email and other business takes place on another computer. Now instead of having to go back and forth between computers, I can simply share the screen of my "business" computer and not have to leave my desk, go over and wake it from sleep and log in etc in order to respond to emails etc. I can now simply share the screen and type away on my work machine using a shared screen. I sometimes have iTunes playing from my business computer in the background - and now I can control it's itunes from my work computer. Brilliant!!! The possibilities are endless!
triggering Automator back ups... file management from the kitchen... running remote scripts...