being 6'3" and 270lbs makes it hard to find shirts that fit.  XX-Large Tall Carhartt shirts are perfect for me.  They stay long, they are nice and thick, which makes them more durable.  I'm not quite a fan of the pocket logo, and wish I could find some of the shirts without pockets at all (possibly for a nice thick undershirt of something).

I have bought about 8 of these shirts, and I liked them all.