chad i have the exact same set up as you except i dont have leopard yet..... does it all run McSweet with leopard?
Leopard is fantastic. Sort of...
I cannot get my printer to work properly with it (Oki c3200n), because there's no Leopard drivers. I'd check to make sure all is well if you have a printer before making the leap.
Aside from that, all is well. SuperDuper! is now Leopard-compatible, so with that and Time Machine (which is pretty and works well), I'm protected in that.
Spaces is a nice improvement, especially if you are running either VMware Fusion or Parallels. You can assign a Space to each full-screen OS window, and switch on the fly.
10.5 was much more stable than 10.4 when it shipped, and 10.5.1 is fast and usable. There are some changes you might have to get used to, but unless you have an application that won't work with Leopard, now is a good time to upgrade. If not, wait for 10.5.2 which'll ship hopefully here in the next couple of weeks.
10.5.2 will probably ship the same time El Jobso makes my 3 month old computer obsolete by announcing a new model.
But yeah, Leopard is "McSweet" nonetheless.
