Spin-off games, definitely. The main series games all resemble each other with predictable and outlandish plots. A minor exception is B/W, which kinda tried to be different and also kinda failed :p I don't think the spin-offs necessarily have great storylines, but I do prefer those plots to the main game plots. The first two Mystery Dungeons have pretty good plots in my opinion, they're pretty much the only Pokemon title I'd play more for the story. But I'd say Pokemon is definitely more gameplay-oriented than story-oriented.