Slate
Slate is a window management application similar to Divvy and SizeUp (except better and free!). Originally written to replace them due to some limitations in how each work, it attempts to overcome them by simply being extremely configurable. As a result, it may be a bit daunting to get configured, but once it is done, the benefit is huge.
I’m happy with Moom, but perhaps there’s some interesting code here if you want to learn how to use the Accessibility APIs.
It's funny. I first created my own shortcuts to Moom-style actions windows for Word docs in WordBasic back during the early Word 6 for Mac days. Took a couple of hours. Attached keystrokes as I pleased.
A year or two later, I recreated the same actions with the same keystrokes using AppleScript and OneClick. Again, just a couple of hours. And since the AppleScripts didn't really change, I was able to make a painless transition to OS X. (And current versions of Word still run those old macros, so no conversion necessary at all there.)
In short, I've been running a consistently triggered, personally designed Moom-style interface since the mid-'90's with very little muss and fuss.
(I find it an fun bit of path-dependency that a lot of of the basic doc management personal interface I still use today is what I originally designed back in the mid-'90's in WordBasic. That's where first I implemented command-space for 'close doc' and command-option-space for 'close doc without saving', for example, and that's what I still happily use today.)