Better summer running: shirt or shirtless?

Summer is coming to an end, but the heat has been staying with us. This has me thinking, which is better, running with a shirt, or shirtless?

I've tried both approaches a number of times and have found that I feel cooler and more comfortable sans shirt. There's something about running with a wet shirt on that makes me feel heavy.

A cotton shirt, or other non-wicking shirt would obviously be atrocious, but if you're using a normal wicking shirt the heat is still a burden.

The biggest objections I've found while researching the topic stem from whether people look disgusting who do it. Who cares what people look like while they're out running? Is it their job to present something you'll find beautiful?

There is little published research on the subject I can locate. Searches turn up only subjective accounts, like this one from letsrun:

Both actually say that a t-shirt is not enough to significantly raise core temperature over running shirtless, even in hot humid conditions. It does however greatly affect the comfort of the individual from their work.
The athlete/subject feels cooler but the core temp is not the same. In fact, one did mention that depending on the severity of the sunshine, a white shirt can actually contribute to lower body temperature over running shirtless.
Now, interestingly, both mentioned that some of the new wicking clothing actually does work to slightly, but significantly, maintain a lower core temperature while exerting in hot environments.
They work better than cotton shirts, and they work better than being shirtless (even though the shirtless stuff is not published yet).
Advantages of running shirtless
  1. Feel the breeze pass over your body.
  2. No chance of nipple chaffing on those long runs.
  3. Less clothing - means less to carry, less to remember, and less to wash.
  4. Get an even tan, if that's your bag.
  5. It feels cooler, and in your mind, that's all that matter.
Disadvantages of running shirtless
  1. Severe skin damage unless you cover up.
  2. Lack of self-confidence if you're not comfortable showing your skin.
  3. Bugs. Your body is a human windshield with all that sweat.
This type of question probably applies more to men than women, and it's surely subjective, but what do you think?