I echo what hoshichiri said, and would also like to add to not sell for the sake of making a sale. And by that I mean, seeing you have something of value and selling it for a "quick buck" in the end will usually result in regret. I did this a few times during my initial foray on eBay, and about 6 or so years ago with some collectibles I had and I quite honestly regret doing it. Granted, these weren't video games, but my thought process was exactly like yours: these go for a lot, and I don't "need" them anymore, so let me capitalize the opportunity. Fortunately for a few of those collectibles I ended up getting again years later for relatively cheap, but having experienced seller's regret was exhausting in a way, and in the end I wish I hand't gone through in the first place.
So, in conclusion, sit down and think about it.