Yeah, I like Freewheeling the most.

There's not much of an old market in Austin - it kinda sucks.

Austin Tri-cyclist has some used bikes - gotta ask about them, they keep them upstairs.

Waterloo Cycles has used bikes - but it's WAY overpriced, and not much selection.

Ozone has some cool dudes working there, but not much in the way of fixed stuff.

The biggest selection of really old and odd stuff would be the Yellow Bike Project.