The gen 2 remakes Heartgold and Soulsilver would be my favorite. Gen 2 has always been said to be one of the best pokemon games. The first half of the game is like any other pokemon game, and while you see some new pokemon introduced in gen 2 you also get familiar pokemon from gen 1.
You get great music for battling, routes, towns and caves. (Sidenote I love the ice cave music for gen 2) 2 new types dark and steel, the safari zone to catch gen 3 and 4 pokemon, and the ability to explore another region after you've explored Johto. I say I've played gen 1 but really I haven't. I've play gen 2 and got to explore kanto 3 years later.
Overall generation 2 is great because it was great sequel, and focused on a new story for the first half. Unlike B&W2 which was a continuation of the first games story.