There are still a few drive-ins, here, near Chicago. This includes one of the top drive-ins in the country, The Midway Drive-In. We also have The Cascade, which I've never been to, among a few others.
It's been years since I've been to one, though. They were fun. Though, the sound sucked. Nowadays, even with car radio, you're not going to get powerful surround sound at a drive-in. You go to a drive-in for cheap movies and fun. If you really care about the movie, you should go to a regular theater.