When you’re zoomed out to the “all spaces” view, you can drag and drop windows from one space to another to rearrange things. Here’s some keyboard shortcuts to improve upon this feature:
If you hold down the “Command” key while dragging a window, you will move every window of that application within the current space at the same time. (e.g. Every Safari window in the current space will move together, but Safari windows in other spaces with not)
If you do so while holding down the “Shift” key, the window you drag will move to the same location on the screen within the new space. (Especially handy for full-screen windows)
The two keyboard shortcuts can be combined to move all windows of an application to the same location in a new space.
You can also scroll through spaces using your scroll wheel or your two-finger-trackpad-skills while in the all spaces view.
As with all the zoomy eye-candy features of MacOS X, if you hold the shift key down while switching spaces or viewing all spaces, it will do so in slow motion. Oooh!