Aaron's Rock & Roll
423 E 6th St, Austin TX 78701
Ok, I kind of love this place. It has the facade of a little Austin gift shop and place to quickly grab a charger or some ear plugs, but it's so much more than that. It has a little bit of everything: Some silly things that could make good gag gifts, some DVD's. But the focal point is the focus on the music. This store is kind of like a very mild Hot Topic, if Hot Topic hadn't gotten all... weird. It's what Hot Topic should have been/tried to be. They have a rather large selection of T-shirts and patches. I've personally gotten quite a few patches, studs, and spikes from here.
Oh, the best part: they stay open late so you can always stop by after a show.