For autox and DE, I have a Shoei RJ-Air, which is an open faced helmet. I prefer the open face helmet for ease of putting on, since I do wear glasses. It's M-95 rated, so I'll need an SA-2000 replacment soon...thinking the G-Force ones Racerwholesale sells for around $150.00.
I've been a part of the full face vs. open face helmet debates from the past. I like the open face ones, (as long as I'm not in an open car or motorcycle), and hopefully the rest of my safety gear will keep me in place if there is an accident.
Plus with an open face helmet, I can look like those cool rally guys. (As seen in the WRC video that was circulating on the web a couple of weeks ago...)
Just my $0.42.
-Zoltan.