Nintendo has just sent over word on a few upcoming Virtual Console games, confirming Adventure Island (Wii U, September 11th), Wild Guns (Wii U, September 18th), and Legend of the River King 2 (3DS, September 18th). All of these will arrive with your standard Nintendo Download thursday updates.
Adventure Island is of course a classic, often times mentioned as a notorious retro game. Although I'm more of fan of the sequels, it's definitely worth checking out if you have patience. Legend of the River King 2 is considerably more rare, and is essentially Harvest Moon: Fishing Edition.