One great shirt from American Apparel is their Tri-Blend TR401.  It's super soft and gives a great vintage look right out of the box.  It isn't however the most friendly to print with.  Since it's made of 50% polyester, 25% cotton and 25% rayon, the discharge-ability is less than desirable.  

We went ahead and printed a high opacity white waterbase on this tri-blend and were pretty impressed.  The high opacity does leave a bit of a hand to the print, but it's much better than plastisol.

A great look on these tri-blends is printing black waterbase on them.  We'll follow up this post later this week with black waterbase on the athletic grey tri-blend.