Which hat ?

[CopperBrompton]

I love my Laser Genesis: the most comfy helmet I've ever worn, and the best-fitting, both thanks to the thumbscrew adjustment system. Not cheap, though.

 

[Headgardener]

Helmets are really designed to be work only by kids mucking about. An adult out cycling has no real use for one unless you are very unsteady with a poor sense of balance? Why do you want to wear one?

Balance alone is not the only reason why I wear a helmet, it's the buggers that travel in vechicles with four or more wheels and don't give you enough room on the road or don't see you (or so they say after you've been knocked off). Bell Venture I my choice of helmet but as everybody says get yourself to your LBS and see what they have to offer.