Dude, I say this to EVERYONE with that same idea.
What provokes you to sell it? Gameplay? Graphics? Online gameplay with the friend code system? I mean, that's fine if you're going to sell it, but just think about what you'll be missing if you DO sell it. I mean, you'll be missing the friend code system, which I guess everyone would love to miss. But you'd also be missing the good quality games for the system, and that in itself is probably the biggest reason to just keep it.
If it's the bad selection of games you despise about the
Wii, then just don't BUY those games! I hear people all the time complaining about that, and they act like someone's holding a gun to their head, forcing them to buy the bad games, when THEY alone have the decision. Yet, they go and sell the
Wii because of the lack of the games they want. :P
My opinion; you paid $250 for it, and you'll NEVER get that much out of selling it, so just keep it. ;)
Hope this helps! :D