Well lets see, I got my Fakku and Hen-tie shirts.
I also have 2 shirts from Mangagamers.(from purchasing items from there booth at past Anime Expos)
Aside from that I have 1 Evangelion, 1 Hellsing, 1 Shakugan no Shana and 1 X/1999 shirt. Haven't really worn them much lately. Then again I don't leave my house all that often ^_^; Nor did I wear them often when ever I did go out.
I'm wearing my kakashi t-shirt as we speak~ but ehm as sleepwear and sometimes I wore it outside but not anymore~ I only own this shirt. Future buying of anime t-shirts possible.
Yup, I'm wearing my nyoron~ shirt right now, and I also have a panty and stocking shirt, a touhou project shirt, and some others that I wore a lot in high school. One of my favorite t-shirts I had in hs was of a bunny girl, and it had "I <3 Hentai" on it. I wore it to school with a smile on my face. :)
I have a good couple of them, but I don't usually wear them. I feel self-conscious about it if I'm somewhere by myself. Especially the hentai shirts I have (nothing on them, but they say that I like hentai).
When I'm with my friends, though, I feel completely fine, but that's because they're all usually wearing something anime-related, too. It's hard to feel weird about your own shirt when your 20-something friend is wearing a Pokemon or Transformers shirt.