A recent favorite purchase of mine is the J.Crew Factory long-sleeve stripe boatneck tee (on sale for $29.50). Thank you to both Fran and Jess for their reviews and sizing tips! I ended up keeping the tee in two colors. I know... duplicates, really? And stripes, again? *sheepish grin* I was originally drawn to the Forever 21 heathered striped top for the bright blue color, but the material was thin (doesn't feel like it would hold up in the wash) and the fit was off (sz S was too tight in the torso, sz M too loose everywhere).
Back to the J.Crew Factory tee. I love the thicker material, bright color, spacing between the stripes, and most of all, the looser (but not baggy) fit and longer (but not too long) length. For reference, I'm wearing size XS which measures: 15" shoulder-to-shoulder, 23.5" length, 24" sleeve length. I'd say the tee is TTS, or go up if in-between sizes. If I were to nitpick, the sleeves are tighter than usual around the forearms. It was slightly bothersome at first, but now I'm fine with because the sleeves stay in place when I wear it at three-quarter length.