I've always liked Arai because they seem to fit me the best. Some others that are really built well are Shoei and Soumy. Like mrmustang said, go to a shop and try on some on. If they don't fit right and you end up wearing them for any length of time it will be a unpleasant experience.
http://www.suomy.com
http://www.shoei-helmets.com/
http://www.araiamericas.com/