Just chiming in to agree that your head's shape will likely determine the brand, then within that brand find what you like the best. I also value something that keeps my round head cool, so I went with the Giro Aeon and couldn't be happier. I've owned many Giro and have liked them all. The venting is excellent and I like the feel on my head. Just about any helmet will meet minimum standards, but as a pp said, above those minimum standards, comfort, style, and head temperature are key. I have another helmet for cooler riding that is less $$ and warmer, so consider the season in which you are choosing your helmet, as well. What may feel fine for me now may not cut it next July when it's blistering hot. However, given your location, that may not be an issue for you. You didn't mention pony tail, but if you put your hair up, there are helmets specifically to help with that.