If you can't decide, go for the paper-in-a-hat (or box) approach: write down all the names of those games on pieces of paper and then draw one at random, then commit to play only that game till you reach the final game credits.

It'll either make you pick a game at random, or really make you realize what you really feel like playing (for instance, you may very well draw FFIX and realize that you're not really in the mood to play it). Or you can do as Ed Oscuro said and multitask -- but be disciplined about it. Set up a time limit, say one or two hours before having to change games.

Count yourself lucky to have all that free time to play... Enjoy it to the max.