I've seen them all, and this is the one that I come back to over and over again for being the most memorable, most enjoyable, and funniest. The best aspect of this series is being able to step back and forth from serious and touching plot to side-splitting funny scenes and lines, without either aspect spoiling the other. This episode epitomizes that trait.
And the funny scenes really play the characters out and allow them to step out of the ordinary situations (for SG1). It's a joy to watch Colonel O'Neill and Teal'c handle Dr. Jackson's pedantic nature, Carter's techno-jargon, amuse themselves with careless whims, and adapt to the frustrating wackiness of their time trap.
The saving grace of this series is that they take themselves lightly rather than seriously.
If you want to introduce someone to SG1, this is the most approachable episode.