There was a nifty chart of racial heights somewhere on the forums.

There's also something about size changing the speed of going through special exits like archways.

Honestly, every time I try to remember or find out what size does and doesn't do, it gets so muddled up in all the things it used to do, since it's changed so many times.

You gain or lose 10 max health with each size point adjustment.

I saw a seven foot Aslaran today. Made me laugh a bit, because Aslaran don't really strike me as the sort to be seven feet tall. More like six, if even that.