I love these threads which seem to pop up every few months. Coming from a family with an OCD hoarding Mom and a collector of things Father, I'm lucky that I am able to let go of things from my collection. Throughout my teens and 20's (I will turn 30 soon) I amassed collections of many things, starting with sci fi magazines, and Star Trek action figures and leading into collecting DVD's, OOP PC adventure games, Playstation 1 and 2 games, and concluding with Gamecube and X-box games.
I assumed that I would have time to play these games, so I kept buying and buying, especially when I would check here every morning for the early EBgames rare Ps1 games that came in stock. I continued to buy, and ultimately ran out of space, so I tried my best to get organized. Now about 2 years later, I have been (slowly) weeding out my collection because I realized that I don't want to own games that I rarely play, or are tedious to play. Similar to owning only DVD's that I enjoy, I have been on a hunt to get rid of games that are too annoying to play (jumping puzzles, annoying save points, bad controls).
Perhaps the best things that I have learned through this experience (and can hopefully pass on to other collectors) :
1. Your collection won't love you back, nor should you love your collection.. it's just things. I say enjoy your collection.. if you don't use it and love it, get rid of it.
2. Rent games! Instead of paying money for something that you may or may not love, rent it to try it out first. In the long run, you will save money because you will save yourself from buying bad games. Plus, if you like a game, chances are that it will cost less than the time when you first wanted to buy it. (My best example was the game Okami. I was planning on blind purchasing it, but then I played it. The game was fun at first until I grew increasingly frustrated by the inaccurate brush stroking during battle and the annoying timed moments where you needed a precise brush stroke. I stopped after a while, and decided that I didn't want to finish the game because I wasn't having fun).
3. Realize that your games will undoubtedly depreciate in value, yet don't let this block you from getting rid of them. If it isn't worth a lot for trade in, just give it away. Why keep something that you don't truly love?
4. If you plan to sell or trade something in... Do it, or lose it. Don't procrastinate. If you decide to sell something, give yourself a time frame where you agree to give something away by a certain date (1-2 months) if you can't sell it or trade it in. Don't focus on how much "money" you are losing, focus on having more free space and time.
5. There will always be some "rare" games, but history seems to support that games will be re-released again in some form. Especially with virtual consoles, many older games are making a return. The question to ask yourself is whether you truly want to play the game again, and if not, why not sell it? Chances are, you will get a nice price, and if not, it's Ok.. you will survive.
My post is mostly for those OCD (diagnosed or not) collectors who continue to collect, yet never find the time to play or enjoy their collections, except for being able to look at it, and wipe away the dust. Keep in mind, that there will be so many more games released in the upcoming years. Do you really want to continue living this way with games that go unplayed? Chances are that your collection will grow... will you continue to feel good about having 100, 500, 1000 games that you haven't even finished?