One of my projects is a scientific app that would not be readily possible on the desktop without Leopard - the address space requirements are too big for 32-bit oses, and doing my own VM scheme without hardware help would be a major pain in the neck (and inefficient too - it doesn't lend itself to being chopped up into large blocks). The server/ui-app model doesn't work well for it either. Fortunately, I can set this thing up with Leopard on a Mac Pro, with 4 raptor hd's in it in a raid 0...