Well, I've got a different tip for switching programs. Though, I don't mind the focus not automatically switching back and prefer it not to. But that might be because I like to use the keyboard to tab through parts of window sometimes and don't want to have to convince the operating system that I really do want the focus in the window I've click into. So, I like the Command-click ability instead of the OS assuming I want to type in some other application.
As stated before, Command-click-drag works with the scrollbar in a window of another app without bringing that window or app forward. And actually, Command-mouse click is quite broad.
For instance, Command-click-drag the title bar of another window and you move it without bringing it forward. However, don't Command-click on the title itself because that will give you a menu of the file path or browser history or something else relevant.
Command-click a tab in a Safari window that isn't active and the window will switch to the tab without bringing the window forward (read: no loss of focus). Try to Command-click different things and see what else you can do.
As for the alternatives I mentioned, since your hands are on the keyboard (you said you want to start typing someplace) these might help. One is the obvious Command-Tab. If you simply tap the Tab key instead of holding it down then you will simply be taken back to the previous app you were using. Very useful for quickly switching back and forth between two apps.
Also consider Command-` and Command-~ (same key, use shift). That usually cycles you through the windows in the current app, backward and forward.
Oh, and one more thing, but a little off topic. You can select text in an unfocused window simply by using Command-click-drag. That will highlight the text in gray (since the window doesn't have the focus). Try Command-double click for selecting, too. Any selection in an unfocused window can simply be Command-click-dragged and dropped any place, even to the desktop as a textclipping. Oh, and of course, whenever click-dragging, it helps to pause at least a fraction of a second so the computer will know you want to move the selected text or stuff instead of creating a new selection.
I find the Command-click actions quite useful since I don't have as much screen real estate. Being able to scroll a window in the back and then select text and then drag the text to the window I'm currently typing in (or even to different one) is quite a click saver and feels much cleaner without swapping windows around. There's really a lot of different possibilities which is great since I've found lots of different circumstances, too.
Just experiment and play, play, play. :-)
The Monitor is the Revolution