I have a sealed copy of Halo 2 I don't want to open even though it really isn't that valuable. On one hand I say to myself, this game was meant to be played, just let it be naked and free.
But it just doesn't feel right for me to tear open the game and pop its seal, not yet. I think that some day it should be opened. We'll see.
You could always buy a loose or opened copy to play - shouldn't run you more than $10. Although I don't specifically collect sealed games, I have a few, and unopened games look good in a collection. I recently bough a sealed NHL 2K2 for Dreamcast for $2. It's by no means rare or uncommon, but it's the last Dreamcast game to be released (at least in the U.S.), so I consider it a collectors item in it's sealed state.
Oh, I do have an opened copy I play

I had to pick it up when I saw it on craigslist for only $5. It's neat to have the sealed copy because it has the 'do not open until release date' sticker there and I vividly remember standing in line at midnight in Colorado Spring back in '04 and then going home to play campaign all night.
Holding the game reminds me of that time again, it's weird. It's a special game also because I used to play with an old roommate who passed away. Playing now feels like a time capsule. I don't know if I'll open it.. Maybe one day I'll give it to someone that wants to play the game but I like having for now.
