that solution
1. only works for text, which is part of eranation's rant.
2. only works if you know the exact height of the container.
3. isn't even centered: http://i.imgur.com/lz8Mq.png
2. Fair enough. It would be nice to be able to set line-height to a percentage of height.
3. Bug, my bad. http://jsfiddle.net/aMMxj/51/
I added a background image with a grid that extends 80px from top and bottom. There's also a small margin/padding/border reset and doctype just to make sure defaults and quirks aren't messing with anything.
To continue down this path of the "natural" way to vertically-center, font-size must also be explicitly set. This works http://jsfiddle.net/nJy8t/3/ . Though it's certainly not without it's flaws (we lose font-size cascading).