For reference, I'm 6', 180lb, 41.5 chest 32 waist.
After almost a year of on-and-off auditioning of various pedestrian-level tees I've settled on American Apparel. During that time I've also tried:
Costco/Kirkland
Pros Fabric quality and thickness are decent. Medium a decent fit for me after hot wash and dry.
Cons Cut huge and only available in M or bigger. Very blousy from midsection down. WIDE neckband and cut long, covers almost my entire ass. Looks very much like an undershirt.
Gap "Best", Hanes "Perfect", Target/Mossimo Athletic
Didn't even bother with these, fabric too thin.
American Apparel
Pros Decent fabric quality and thickness. Large in heather gray and brown are a good to excellent fit for me in chest, shoulders, and arms after a hot wash and dry. After a bit of minor tailoring (see cons below) they fit pretty much perfectly, hitting top-to-mid bicep and ending at about the top-third of my back pockets.
Cons Significant variation in cut/size depending on color. Navy and white, the other two colors I own, are 1-1.5" wider in the sleeves (laying flat) than gray or brown, all size L. Also, these shirts are the ubiquitous tube shape so they are completely straight up and down. This means a good fit in my chest and shoulders will also give me a tent-like midsection, so all my AA shirts need a taper from the chest down by 2" to fix this.\
American Apparel measurements (heather gray, LARGE, post hot wash+dry)
Chest (pit to pit) 20"
Shoulders 18"
Sleeve length (from top shoulder seam) 8"
Sleeve width 6"
Length 27.5"
Pics to follow.
Edited by hyt123 - 3/27/12 at 7:30pm