IMO, Season 1 is pretty bad compared to the rest of the series. My tendency is to start with the movie & "Children of the Gods," then skip ahead to the last 3 episodes of Season 1-- "There But for the Grace of God," "Politics," & "Within the Serpent's Grasp."
I'm interested in Season 1 but mostly only as it relates to the better, later episodes of the series. The show doesn't really find its footing until Season 2. Then it hits a sustained peak during Seasons 3-6. Seasons 7 & 8 have some good arc stuff but also a lot of filler. Seasons 9 & 10 are a completely different (though still very good) show.
If I wanted to get someone hooked on the show? Hmmm...
My first answer: Show them "Within the Serpent's Grasp." Yes, it's part of a 2-parter. But if they're not begging to see "The Serpent's Lair" after that, something's wrong.
My 2nd answer: "1969" is just a heck of a lot of fun.
For some good, representative stand-alones, I'd suggest "The Other Side," "Scorched Earth," & "The First Ones." I think the best introduction to the overall tone of the series at its best comes from some of the episodes that really get into Daniel Jackson's humanist side.
Daniel Jackson tends to be the best gateway character into the series, IMO. Col. O'Neill has some great moments but I don't think he ever got the really solid, juicy episodes than Daniel often did. Samantha Carter is a fine character but often gets too technobabble-y. Teal'c is probably my favorite character but I think you have to really become invested in the cast & the mythology before you can truly appreciate Teal'c. (Once you do appreciate Teal'c, do not hesitate to pop in the "Exodus"/"Enemies"/"Threshold" arc.)