Ok, I promised a friend I wouldn't do this, but I have to, just to prove the current screenshots are not real. These are the real ones I will show you. The first thing you will notice with 10.5, Apple has done away completely with pin stripe, it does not exist, its a cleaner look and feel, also, there is a small take on using translucency in certain parts of the UI. But this is for inactive windows as can be seen in the About This Mac dialog box. The dock also reflects this but is permanent throughout the user session, its a subtle change, in active icons seem greyed out on the Dock, while running icons are brighter, this is considered to be a Visual cue.
The biggest change has to be the Leopard version of Boot camp, actually, its nothing like boot camp, its way superior, its Virtualization running at the hardware level, no drop in performance, of course, XP and 2000 are assigned with 128 and 64 MBs of RAM respectively. Of course, some of this might change by WWDC since these screenshots are from March around the same time Boot Camp for 10.4 was released. There is expected to be a whole lot more coming, but, currently, OS switching is probably the biggest right now. I have a screenshot of the new Finder, its a bit too ugly right now and its a work in progress, you don't want to see it, trust me, and its not brush metal either.
Other noticeable things, Recycle bin, not on the Dock by default it seems, although I don't know if this is user intervention.