This question comes from The Bitter Script Reader, via Twitter: For spec pilots, should you write the first ep, or write ep 2 instead so you can present a "typical" ep?
That's tough - because I think the answer is: both. I don't mean you should physically write two scripts; I think you should write a pilot, which is the first episode of a show, but that it should also be a kind of typical episode that gives us a sense of what future episdoes will be like. It's a really difficult task, especially if you're writing a serial drama. In a sitcom it shouldn't be that hard.
But let's say you are writing a drama about a guy who enters a new world for the first time. It's a premise pilot - a show based on something big that happens in the beginning. And obviously, you need to show us that big thing. But if you write something like this, you may get notes like, "what's the series?" or "what's episode 10?" or "what's the arc of this show?" So even if you do opt to go a very premise-y route, you should have these answers in your head, and try as hard as you can to infuse your pilot with the seeds of the rest of the show. Part of this, I think, is setting up series conflicts.
I think another strategy is to make sure you have an episodic pilot story in addition to any sort of big premise world-setting-up kinda stuff. A great example is MAD MEN, which is probably the most succcessful spec pilot ever (although, yes, it took years to get made). In the pilot we get to know all these people and the world and stuff, but we still have the episodic plot of Sterling Cooper putting together a cigarette ad campaign. This lets us know exactly how ad campaigns will be handled as episodic plots in future episodes. (It also was a nice self-reflective comment on all the smoking you'll see in the show.) Genius, eh?