False gods
Most people probably think Stargate is the trashy kind of Scfi made only for popular audiences. Indeed, this is true, Stargate is focused on pleasing the audience. However, even the trashy Scifi's come up with some interesting topics. The major focus for Stargate seems to be on the idea of aliens posing as gods. First, there was the Goa'uld - parasitical worm-like creatures that enter the brain and take over the body. Currently Stargate command is encountering the even more dangerous Ori (Ascended beings that demand to be worshipped) The Goa'uld took the persona of Earth's ancient gods, such as Re, Baal and Anubis. The fact that they are not true gods means that earth worshipped false gods in the past. The Ori seem reminscent of the ancient Roman Catholic idea of God - worship or be destroyed. They are not loving gods as the Christian God is. So what can we say of all this? All "gods" are aliens? Okay, maybe not. But what we could say is - don't get taken in by the hype. The Ori have power - but it doesn't make them gods. It's when a god cares for you that makes them worthy of worship. Yes, Stargate is for popular audiences, however it does contain some interesting insights. For by looking at what is popular, we see reflected, popular ideas and beliefs. That's why popular culture is an interesting study.
Passionate Apathy
Sci fi is about the only genre where one can speculate and tell stories about the nature of Gods. Believers can then comfort themselves with the "It's only a TV show" mantra; they tend to get twitchy when you refer to their holy book as sci fi.