I love a guy with nice arms. But dudes, at least just around me, don't wear a tanktop unless you plan on shaving/waxing the jungle under your arms. Jesus it is so distracting when there is hair longer than my head hair, peaking out from the sides of your armpit. What the hell does the deoderant do? Oh lord. If i ever get a boyfriend i will shave his armpits whule he sleeps. NASTAY. Unless you have really tamed, thin, barley there hair under your arms in which it shouldn't bother me too much. Sorry i go on too much it is just unapealing to me.
Sure, if that's what the guy wants to wear. Especially if it's hot out... he should feel comfortable. :) I was talking to my neighbor and he wears tanks because it's so hot outside... and sometimes I casually glance at his arms when he motions around. He looks good haha.