ADS has a nice variety of G/A traffic, and an occaisional BBJ
or private 737-200 (N370BC is based there). The south end of the field (Arapaho Road and Addison Road) has plenty of space to park and observe.
I am not very familiar with the north end of the field, but I do remember that it's very developed, not many open spaces (that I'm aware of, anyway). Midway Road runs alongside the northwest corner of the airport, and if you can find places to park, that might be a good spot in the afternoon or evening.
[Edited 2008-08-26 17:30:38]