I have Tiger and had generally decided that I'll take the approach of buying every other release of OS X rather than buying every single release (so, 10.4, 10.6, 10.8, etc). However, I'm considering getting Leopard anyway just because it is supposed to be the biggest release of OS X yet. Wat's a good guess on how long will it probably be until the next OS X? A year? 1.5 years? I consider the incredibly advanced filesystem that'll be coming in the next version to be a huge deal. Does anyone know any other things that are pretty certain to be part of the next big release (things that didn't quite make it into Leopard, for example)?