Well, you just sold one
I'll give it a try, I like the design enough and I love the stuff you do... Never bought something though, because most of it is a little above my price limit - but if the shirt fits and the quality is good enough, I could see myself buying one every once in a while. I really like your designs, so I'd love to wear some of those - not literally your posters, since they might not make a good shirt (they make fantastic wall art though), but your art style.
Just to give you an idea, what some of the shirts are that I bought and liked so far:
And my favorite game related shirt:
They don't have to be subtle about being about movies/games/whatever, but I don't like it when they hammer it home and are too much in your face. I don't like too much text in my shirts and if I chose to wear something about a game or a movie, it better be a good design

The thing is - most of the sites that have a daily shirt on rotation mostly offer black shirts. I don't like that too much. Many of them are way too busy or feature too much text or try to be funny when they aren't...
This is on daily rotation on a site today. The left one is way too busy and tries to bee way too clever for it's own sake. The middle one I don't really care for, but I can't nail why and the right one I might even buy, but not as a black shirt.
No idea, if this is in any way useful to you.
I'll remove those pictures if they clutter up your thread too much.