I go with a general rule: if the game has a good working translation, it's one that's worth the trouble because of all the hard work that goes into it. The only game I view as an exception is Sengoku because I wasn't even impressed with the NeoGeo original. That said, I have a few. I'll leave out the ones usually brought up as I'm sure someone else will (Live-A-Live or FFV for example are amazing, but brought up a lot).
-Marvelous: Think Zelda, but it's all puzzles and observation. A really fun game that especially shines during the spring or summer.
-Wrecking Crew '98: Neat little puzzle game. It has the original Wrecking Crew inside too.
-Super Robot Wars Gaiden: A pretty good place to start on the franchise while Gideon updates SRW3.
-I Love Golf! O.B. Club: This is a really fun one with friends. If you liked Kirby's Dream Course/the game it's based on, it still retains a similar feel except it's more like a mini-golf course (putters, no enemies and instead you have normal minigolf hazards, etc.). This is the best golf game on the console, bar none.
-I Love Bikes! Street Racer Soul - Rider's Spirits: This is kinda like Mario Kart on motorcycles. You can get by without a translation, but you'll be glad that you have one.
-The Stories of Ihatovo: A really nice adventure game that's written well (along with Tom's usual quality). This deserves more attention, there's not even a review up.
-Mysterious Dungeon 2: Shiren is a perfectly good roguelike that can get addicting very quick on the SNES. If you've played Pokemon Mystery Dungeon, that series is a spinoff of this one.
-Dark Half: An RPG that did something different, in that the game has you switching perspectives between the good guy and the big evil. Both play very differently, and the atmosphere is a fair bit more er... dark than the usual fare. Also the plot is pretty well done.
-Breath of Fire II: the original translation was er... bad. So take the retranslation.
The SNES also has a boatload of japan only games that are not only pretty fun, but are more than playable without a translation. Unfortunately the only way to sift through all of that is by either playing them one by one, or by someone like SNESDrunk who goes through most of the catalog in general.