I use a Mac and switch monitor configurations multiple times a day (I'm either using just my laptop display, or using my huge monitor + laptop display). I typically use a couple of different window configurations (Safari, Vim, Eclipse, XCode, Terminal, etc.) but it's different depending on whether my laptop is connected to my external monitor.
So I wrote a couple of Apple Scripts that automatically position my windows on my screen based on the coordinates provided. Here's an example of it running as a published app on my laptop. I just go down to my dock and click on the app and presto my windows are arranged.
I've put a couple of examples on GitHub: https://github.com/cassell/Mac-Window-Positioner
Jan 19, 2012