I'm not sure if this has ever been a topic, but from each of the 5 seasons, which has been your favourite stand alone episode. It may be an episode that concludes a story arc (such as The Prodigal - it ended the Michael arc) or it may be just a regular episode (such as Sunday). Episodes that were originally aired as a 2-hour episode but were later split are acceptable (such as Rising) but 2-parters are not (such as The Lost Boys and The Hive)
Mine:
S1: Home (because of Hammond's only appearance)
S2: Critical Mass
S3: Sunday
S4: Midway (because of Teal'C and Ronon)
S5: Enemy at the Gate
Mine:
S1: Home (because of Hammond's only appearance)
S2: Critical Mass
S3: Sunday
S4: Midway (because of Teal'C and Ronon)
S5: Enemy at the Gate