is this hand drawn? If it is I'm impressed. It seems a little weird on a shirt though. A little too big and way too complex. The candle seems to long and the placements a little off. However the cake looks yummy :D i want some cake now! Aw....how sad for me...but back to the design, I don't feel like your message is strongly conveyed in the image. Like i don't think i would look at this and instantly understand.(Nothing against intelligent tees but still) But maybe I'm just slow...
Hmmm... I might change the placement to like the lower right or keep it centered in the chest area... to me it just seems kind of weird where it's at. I like the artwork though.
I think this is the strongest so far. Still, while the drawing is lovely, I think the concept is a bit week. Maybe if you tried a different shirt color. No matter what, this an excellent illustration.