Performance commuter jacket and a helmet cover if it's really comming down. Works pretty good for me. It has pit zips, velcro on the wrists, some butt coverage, and the hood zips off. If you go hard you get wet from sweat but I haven't found anything including my very expensive gortex jacket that I won't work up a sweat in.
http://www.performancebike.com/bikes..._400000_400070