i have a MET BadBoy helmet - theyre really good.
i have had it for ages now - before they were properly released but theyre comfy, strong and reasonably priced at £25. However i paid £30 for mine because they werent even released at the time!
Tom
MET BadBoy:
also giro havocs are very good: 05 version:
try Bikedock or Chain Reaction Cycles