What's your price range?

If you're looking at lower-cost helmets, I'm a huge fan of my new Bell Alchera. My previous helmet was a cheapy Schwinn. The Bell is insanely breathable and it looks pretty good, IMO. They're only like $40 on Amazon, and I think I got mine from my LBS for around $50.

Not sure if this applies to you, but I have a huge head and the size large fits me beautifully.

Definitely try a variety of helmets on before buying.