[Sand4fish]

Retro games in general hold up their value pretty well and only tend to go up in the future. The problem with current generation gaming is that the term "limited edition" is pretty much coined to every game. If you want a safe bet investing in the short term, buy only editions that are numbered or limited to a certain amount, preferably less than 10,000. Other than that, buy only games which IP's are new (safe bet on console exclusives) but stay away from big companies like naughty dog and konami, as they have the cash to mass produce and advertise their product. Demon's Souls, a ps3 exclusive coming from a rather small publisher (Atlus), has high prices for their special editions and first edition on ebay though the game has been re-released in the market as "ps3 greatest hits".