But I'm always glad that I collect games b/c I know if I ever need money, I need only sell off part of my collection. And since I never pay high prices on my own stuff, I know that I'll probably be making a little profit if/when I have to sell stuff off.

I've never found price guides to be very valuable. They tend to pretty much always be off, by a LOT. But at this point, I kinda know the value on most games, and if I don't, I can always look up completed auctions on Ebay or (if it's something I only want to flip) look up the price on Amazon. Regardless, I always make sure I'm not paying "full price" for any game I purchase.