SLC has two main runways which stradle the airport, 16/34 (L&R). There is also a 17/35 runway, but it is situated far from the terminal and only seems to be used during heavy peak hours. The facilities at SLC are nice and are well decorated by an exhibit which displays pictures of Utah landscapes and landmarks. Delta 757's and 767's and are prevelant here, but most of the traffic is made up of smaller stuff.

Delta L-1011 departing on 16L. View from the public observation area.

INDOORS:
-Smoking room between Concourses A and B. If you smoke, or you are willing to put up with smokers, you'll probably have a better time at SLC. Some of the best indoor spotting locations are in smoking rooms, and this one may be the best indoor view of them all. Good view of departures in either direction on 16L/34R and a good view of arrivals on 17, when they happen.
-Smoking room in Concourse B near Gate B11. Good view of post-rotation departures on 16L. Again, it's in a smoking room, but the view is interesting because you're practically right below the departing birds.
-Concourse A, Gate A8. A really strong and up-close view of departures on 16L. View is reminicent of the great view from Terminal 2 at PHX.
-Concourse A, Gate A7. Good view of arrivals on 34R.

Delta 767 on short final for 34R. View from the public observation area.

OUTDOORS:
-Public Observation Area. There is a great public observation area at SLC behind the perimeter fence on the southern end of 34R. You'll find the lot sandwiched between the FedEx facility and the golf course (I'll never understand why people build golf courses near airports). This lot is especially a treat when the action is to the north...arrivals pass right over you. Lay out a blanket on the grassy knoll and look straight up to enjoy the action.
-Central Parking Garage. From the top floor of the garage you can get a commanding view of the airport. The north end of the garage provides the best view. Great view of downtown Salt Lake City as well as the beautiful greenery of the nearby golf course.
-West Parking Lot/Parking Lot B. From this parking lot you can get a nice view of 16R/34L. The view of arrivals on 34L is the best feature here, and departures on 16R are a treat, too.

Delta 737 departing on 16R. View from Parking Lot B.

PRE-9/11 SECURITY REPORT:
-For a smaller airport, security presence at SLC is surprisingly tight. The parking garage is regularly patrolled, and security seems to take notice of loiterers. During my last trip there I was filming from the top floor of the garage...I noticed a security guard who had stopped and was watching me from across the garage. Also, if you stand on the northern edge of the garage, which provides the best view, you are easily visible to security guards patrolling the terminal entrances. The parking lots are regularly patrolled as well, but you can avoid them by standing near the bus stops. There is no security presence in the public observation lot. SLC has quite a strong presence, so be careful not to chance it, for they will take notice and possibly ask you to leave.