I've always gone for Arai in the past, always top of the range ones too, robbin' bastids that they are!
I've been using a Reevi flip front for the last year or so, bloody brilliant bit of kit!
Lightweight, quiet, warm (even commuting from Lenzie to Bellshill in December) and the rear view system is splendid too.
I got my from Nooj, an exfoccer, but Bikes on Parade up in Dennistoun sell them too.
Just on Alexandra Parade on the opposite from the Royal, pretty much the first unit.
Tony is a good bloke, worked with him a couple of years back, sure he'd look after you if you popped in.