I participate in the hobby to build dioramas.
In 1995 I was thrilled to see what was then the most realistic renderings of the Star Wars characters in plastic (that R2D2 is still fantastic!) and there were only 9 different ones.
I had the opportunity to buy to recreate the movie scenes and gather together the appropriate number of Stormtroopers to outnumber 6 good guys (if you count the droids).
Then of course it just blossomed from there in terms of both what Hasbro was producing and what I decided to buy.
I never decided to "collect" in order to have everything they made though. The first figures I consciously remember passing on were the "All New Likenesses" of Luke and Leia, as I already had these characters and THEN (in 1998!) started resenting Hasbro making minor improvements to characters I already owned, so as to try and entice folks to buy the same guys all over again (and Luke Tatooine kept being rolled out there, as he was even this year in Phil Collins disguise).
But I never set out to be a "collector" in the proper use of the term. It's the best "most general way" to describe what I do to non-participants in this hobby, but I NEVER was a completist.
Each non-movie year I might scale way back just how much I buy. But with about every conceiveable army building opportunity done (aside from Expanded Universe Yuuzhan Vong warriors), I don't forsee myself chasing all these little product changes like a blue-coat Han Hoth in a giant, deluxe Target battle pack (honestly, I don't even want that).
So where are you in terms of what you're buying or want to buy (wish list)?