SizeUp

Allow me to recommend SizeUp. It's a Mac app that lets you manage your windows without using a mouse. It's super-cheap, you can name your price, as low as $3 for a license. There's a free demo. I use two monitors, and use SizeUp to bounce windows from one to another. This is very handy when I'm writing on my primary screen and have a reference or figures on the secondary screen. I love being able to put windows side-by-side, pixel-perfect, in just a couple of keystrokes.

I think the most pedantic use I have for SizeUp is that I don't want my maximized windows to go all the way to the dock, I want to leave a strip of exposed desktop so that I can bounce files around easily. I don't like thinking about where to save files when I save them, I save everything to the desktop, and then file everything a couple of times a week. This way, I don't hit speed-bumps with thinking about organization when I'm doing creative work.

Also, I keep my dock on the side of the screen. Rows of about eighty characters are optimum for readability, so I prefer tall, narrow windows. Most apps don't respect that, but SizeUp obeys me and beats unruly apps on my behalf.

SizeUp lets me resize and position windows automatically so that I don't have to fiddle a lot.