Leopard looks good and may be better, but Tiger is very mature and pretty much all apps run on it. When Leopard comes out, it's going to be a while before the apps are ported to run (or run better).
I had a similar problem when I moved from Panther to Tiger. Had to keep Tiger away from my work computer until my important apps were updated.
So, I would say buy now and then upgrade later when it comes out. You may find out that an app you need may not be ready for Leopard.
It's Leopard (10.5) rather than Panther (10.3). Don't want you downgrading your installation.
And, yes, there will be issues at first. Plus, as iPhone users, we get to have the Apple Store credit that can be put toward a copy of Leopard.
All these cats... LOL... yep, meant Leopard..
