I'm a south Florida triathlete and on my training rides I typically wear bike shorts (I prefer anywhere from a 5" to 6" inseam) and a tight fitting tank top. I've never ridden in a bra top on the bike, although I must say that I only ever run in a sports bra... I never, ever have a shirt on (unless it's colder out that 50F- which is like 2x per year here). It's just too hot.

I actually race up to a 1/2 iron distance in a workout/competition two-piece swim suit ('The Finals' makes my favorite two-pieces) and that's pretty much the only time that I'll be on a bike with just a sports-bra style top.

Many, many peole have already written this... but I think actions speak a heck of a lot louder than the "clothes" that someone has on. In South FL, I typically see people with a lot less clothing on than I would see up North. My very best friend often rides her bike on training rides in just a sports bra; but she certainly isn't trying to seek attention from it... it's just a heck of a lot cooler!

Good thread!