I've never understood buying something and then keeping it in the original package, because I never consider resale value. If I buy something, I want to play with it.
I buy 2 and keep one in the box.
Usually though its to keep one set intact while my boy loses the pieces to the other while playing with it.
Are there really any Star Trek figures that have gone up tremendously in value over the years?
The more older and rare (not widely distributed) figures have, but not so much those made within the past 20-25 years, with a few notable exceptions, naturally.
The things that have really
gone up big in value are ship and role-play toys as well as the more obscure novelty toys.