I would have a video games store, or a place that sold comics, manga, action figures, and games. I would even have a 'adult' section with hentai/yuri/yaoi, and some 'interactive toys' in the back and check ID. It would be cosplay friendly; and if there was demand for it I would have a lounge area where people could go hang-out...with game systems...and maybe karaoke....and board games.
I might just do that someday as the idea has made me giddy >.> but it would cost too much to start alone....
One of my high school friends and I used to say that we should open a small manga café that sold soup, sandwiches, tea, manga, and comics, perhaps with a small area for tabletop RPGing, too.
Hmm. I think it would be very interesting to have a business specializing in creating historical clothing, but that's not where my talent lies. Instead, I'd prefer something that's highly independent and involves very little human interaction. If I knew what that something was, then I wouldn't be fumbling through the dark now.