I ride with this..
http://www.bellhelmets.com/index.cfm...ategory_id=882

Shield slides up under visor. Drop it down for rain or cold. Love it!

 

Bell Mag 8 is a great helmet with a good fit between the helmet and the shield. It's my daily use and day trip helmet.

I use a ff (Arai) for longer tours since it provides a better seal between the helmet and the front of my rain jacket but I'm sure you're not interested in a ff in the hot south.

 

when it gets bad, i either find the nearest car wash to slip in under the canopy of, or a underpass if it's really bad. only thing wrong with the underpass, someone in a car might feel the need to occupy the space that your bike is taking up. and run into you. i really tend to watch the sky and try to change my route if i can to avoid those rain type clouds.