There's something about the Greek ampitheatre concept that makes you feel plugged into existence -- art and music in the round and in the raw and celebrating the natural landscape in which it's set. It just feels right, goddamnit!
The Hollywood Bowl isn't quite Epidauros, but the seats are a little more comfortable ... and it does have a damn fine soundshell that projects the performance to the whole audience.
UPDATE: Science Daily points out the near-perfect acoustics at Epidauros are almost wholly due to the decision to construct the seats with limestone, which makes the perfect acoustic filter for voice production: "Researchers at the Georgia Institute of Technology have pinpointed the elusive factor that makes the ancient amphitheater an acoustic marvel. It’s not the slope, or the wind — it’s the seats. The rows of limestone seats at Epidaurus form an efficient acoustics filter that hushes low-frequency background noises like the murmur of a crowd and reflects the high-frequency noises of the performers on stage off the seats and back toward the seated audience member, carrying an actor’s voice all the way to the back rows of the theater." [Hat tip Eric Olthwaite.]