Another vote for Ohio. Man, with few exceptions, every Ohio driver I've come accross has been a complete idiot.
I lived on Hilton Head Island for a while, and we'd get sh!tloads of vactioners from Ohio. They were the WORST drivers.
My susicions were confirmed when I visited Cincinatti a few times. Oh boy, was THAT place an adventure to drive in...
BTW, in my 17+ years of driving, I've driven in most of CA, AZ, NM, TX, GA, SC, NC, IL, IN, MO, TN, AL, UT and a few more. Ohio still takes the cake.