By the way, this is a shirt I ordered for my son:
All of my shirts are printed digitally by Spreadshirt, and I've been really happy with the quality. I especially like how my watercolour drawings are rendered. Here's a close-up of my son's t-shirt (which had been washed and dried several times before taking this photo):
Not all of the shirts have this look. I converted some of my drawings to vector graphics for some of the tees, because they looked better and bolder that way -- I made changes to some drawings so that they would work better as t-shirts.
Celebrate your artsy fartsy-ness:
I've used American Apparel tees whenever possible, however they are a bit more expensive in Europe. I wanted to stick to sweatshop-free tees, and I haven't tried out other companies at the moment. Continental looks promising though, and is offered by Spreadshirt. Anybody familiar with them?