I think something that can help save your life is definitely worth a shot! It's true that they are really hot in the summer
But overall I think it's worth it, at least for me, I know a couple of people who would have been killed without one, and as it was they got hurt pretty badly, so whenever I don't feel like riding with a helmet I think of their accidents and it's always enough to make me put one on.
As for looks...they have some out there that are pretty snazzy and professional looking and do the job, mine is sadly not one of the good looking ones
Looks like I have a bubble on my head...sigh...