I haven't purchased Mac OS X "Leopard" yet, but when I do Spaces will be the main reason for my purchase. In my earlier Unix days I used the multiple desktop feature quite a bit, and I look forward to using it again.
That being said, what I'm really interested in today is how Spaces might be implemented from a design perspective in Mac OS X. What I mean is that -- without seeing Spaces -- how do you think it will work with Mac applications and the Dock? With the Dock and Menu Bar the Mac UI isn't the same as the older Unix UI's, and I'm curious how they'll implement certain features.
For instance, one application I use is The GIMP, and it's a multi-window application. If I move the GIMP to it's own space, I hope it will open all new windows in that space. But, if I'm in another space and I click on the GIMP icon in the Dock, what happens? Does OS X automatically switch me to the other space? Or does it stay in the same space and something else happens?
And by the way, what does the Dock look like in the different spaces? Is it the same in each space, or somehow different?
What if I have two TextMate editor windows open (one is in the first space, the other is in the second space), and I'm working in the third space, and then I click the TextMate icon in the Dock -- what happens?
Can I have different backgrounds in each space? How does the [Alt][Tab] functionality work -- does it group windows from each space?
Of course there are many other questions, but these are the first ones that come to mind.
This type of thought exercise reminds me of the Code Kata site, which contains thought exercises for programmers. What I'm thinking is similar, but more of a "design kata", or design exercise. I'm going to write down what I expect, then compare that to Spaces in Leopard after I purchase it.