I also just buy items I intend to play at some point, even if it's out of curiosity (just bought Kirby's Mass Attack since it's on sale for $10; never got into the Kirby franchise, but figured it was worth the $10 to try out or gift).
Where it gets tricky is with pre-orders... I'll buy them with the intentions of playing them, but I hate paying retail price when it's likely that by the time I'll actually get to play them, they'll be worth a fraction of their launch price.
But with LEs and companies with limited runs (i.e. Atlus, xSeed, etc.), it always feels like a gamble to not preorder most of their titles...