I flew Turkish Airlines this spring to Istanbul and back and was impressed with the service and the food. Ataturk airport is a prime place for people-watching and has high-end shops for browsing and decent restaurants. If you do decide to get an e-visa (very easy over the internet - I think it was $30 or so) and leave the airport, be sure to leave adequate time coming back to get through the security check-points. We had to go through four to get to our gate. Don't be nervous about the heavy military/police presence at the airport (and everywhere else, for that matter)....they are there for your protection. For a relatively inexpensive trip into town, you can catch the metro, then a tram to Sultanahmet, where you will find plenty to keep you busy. If you plan to visit a mosque, be sure to have a large scarf to cover your head and usually you'll have to take your shoes off, so make sure you have your good socks on - lol.