Look into Aviva car insurance. They're the only insurer over here that took into account my US driving history and no claims. I did get quotes from other insurers, but they all treated me like a brand new driver, so the insurance rates were outrageously expensive. I got my UK license (automatic) back in October, and I've stuck with them.
I've kept my Ohio license. Last year I spoke to a rep at the BMV and explained my situation. She told me that I can still maintain my Ohio license living in the UK. I still hold an address in Ohio, too, so it's not like I'm just using a random friend's address or something. My license comes in handy, plus there's a strong chance we may move to Ohio in a few years, and I don't want to retake another test (though now that I've passed the UK driving test, I feel I can pass most anything!).