I'm like Bruce. I'd rather get to the airport way early and just take a book with me once I'm through security. Going out of London the other day, we had to be out of our flat by eleven and our flight didn't leave till 4:30. So even after the cab ride to Heathrow, we had four and half hours to kill. Fortunately, we were travelling business class, so no lines (fast-track check-in)and we could wait in the VIP lounge, but the nice thing about Heathrow is that once inside security, there's a vertible mall of shops from book stores to Harrods that one could browse before going to the lounge.
Once at Chicago, we had to go through customs (first port of call) and then re-check our luggage and go through security again for any connecting flights, but this also wasn't a hassle as I had left two hours time between flights and we had plenty of time to spare before our Cincinnati connection at 9:00pm. But that somehow didn't stop the flight from inexplicably being late and us not leaving until 10:40. No explanation was ever given as to why the plane was an hour and forty minutes late, however.