I agree about the yellow tang. I wouldn't keep any tang long term in anything less then a 4 foot tank. Even then, only some species would I place in a 4 footer.
For a tank your size, a nice medium sized fish for you would be a dwarf angel like you said. My two favorites are the flame angel and the half-black angel..both of which I have in my tank.
You should start out with a couple of clowns or something and wait until the tank has had time to establish(like jwtrojan already said), before adding an angel.
I couldn't imagine buying a small yellow tang for my tank and watching it grow for a year or two and then having to get rid of it when it got too big.