Well, I typically only emulate if the game wasn't translated into English but fans translated it for emulators. Ex. Dragon Quest 3 (android version came out recently with an english version though it ditched the animations), Arabian Nights, Dual Orb 2, Eternal Filena, Emerald Dragon, Inindo, Lennus II, Live-a-Live, Treasures of Rudra, Mystic Ark, Treasure Hunter G, Ancient Magic, Bahamut Lagoon, Mother 3, etc... I could go on. But you get the idea. Some of these are pretty awesome titles with interesting concepts and stories that I would otherwise not get a chance to play outside of emulation.
I am with Fuzzy on the idea that as long as you can purchase the game outside of collector channels, then do that because it supports the devs. Otherwise, I think it's alright. Just my two cents.