From the preview last year, Leopard has a number of features that I want to be using.
1. Improved spotlight. A lot of my research material exists in PDF format. Spotlight has already been an invaluable tool. Improvemnts are just going to make it that much better.
2. Spaces. The ability to group apps into different screens will help in my current workflow.
3. Time Machine. Yes - I've got automated backup at the moment, but this is intigrated much better into the OS. I'm planning on tossing a third disk into my Mac Pro for this.
4. Improved speech synth. Getting the Mac to read back text is a fantastic way to edit. Helps pick up gramatical errors and give a far better idea of how what has been written will read. The improved synth will be a big plus - probably the main selling point for me in fact.
5. Mail improvements - the To-Do intigration looks like a feature I'll be using lots.
Everything else is gravy. Optimisation of the new intel Macs. 64 bit support. Core animation. An improved finder (please for gods sake an improved finder).
Now if only Apple would release iWork 07, I could ditch Word and wave good-by to MicroSoft forever
As I have three Macs in the house - I'll be after the Leopard family pack whenever it becomes available.