I like t-shirts but finding decent looking ones that aren't over priced and actually fit me properly can be a hassle. If I could be guaranteed that the sizing would be right I'd get one from Design By Humans. This site has designers submitting their ideas, that are printed up into t-shirts that can be ordered from the site and has a voting system for t-shirt of the day. There are heaps of great designs but being a conservative person, many that I would not wear.
Like this one. It's cool but a 40 years plus person like me would look a bit dorky in it.
This has a very unique concept - zoom in to see all of the meta- phoric map names. Again, white t-shirts don't suit me at all.
I could see myself in this. Now, about that sizing...