One of the nice things about Spaces is that when you click on an app in the dock, you automatically go to the correct space for that app. I just discovered if you have multiple windows from the same app spread out over several spaces, each click of that program's dock icon will switch you, in turn, to each space that contains one of its windows.
This could be pretty handy for Sys Admins who may be monitoring several processes in different terminals from different machines in each space. Each click of the Terminal icon in the dock will take you to the next "machine." One click access to different spaces, rather than ctrl-# (or arrow), or using the mouse to select a space.

