[quote name='ferant316']PS2 era is still too recent for them to be worth anything. I could be completely wrong, but I predict 5-6 years when there aren't still sites/stores like this that have the games new that they could fetch a decent amount to collector's.[/quote]
Well, in that case you could also argue that *any* good game that is kept sealed will become valuable and collectible in the years to come, as sooner or later retail stores will stop stocking games from more than 2 generations ago.
Even the Square PS1 games aren't as valuable as many think. Personally I define valuable as being worth more than its original retail price, and I can only think of a handful of Square games that fulfill that criteria - FFVII, FFVIII, and one or two others.
Most of the rest, unless sealed, go for about the same or usually less than their original MSRP. The likes of Parasite Eve, Front Mission 3, Xenogears, etc.
Of course the sealed ones would likely fetch three digit prices, but that's a hard market to deal in (both collecting that many just to sell and profit, and finding sellers who would be willing to pay that much).
I wouldn't bother with all that personally, as it's too much trouble and speculation just for at best maybe $50 profit per game, but it's cool you feel that way.
I'm a collector (in addition to being a huge Square fan) too, so it's hard to control my urge to just buy any cheap sealed Square games I see occasionally.
So now I usually just keep a sealed copy for my collection, with another opened one to play.