I think a lot of people like Pokémon, including me, so I don't think that works. I'd say racing games, I don't know a lot of people who like racing games, and I think they're alright. Specifically I'd say Gran Turismo or Need for Speed. To answer the question in reverse, I'd say RPGs. Everyone likes those, except for me (except for Mario & Luigi: Superstar Saga!)
None of my friends have the urge to catch 'em all like I do. It's so bad, I'm thinking about not getting White 2 and Black 2... I've even offered to buy copies for my friends so I'd have someone to play with. It never works.
I have the same problem. Most of my friends/cousins don't really like Pokemon. There are a few though, but I still never really get a chance to duel them or trade. I usually pick up both copies of the game at launch and the guide and then just trade back and forth using 2 DS systems.
I don't think I really have a lot of games to add to this list though... lets see...
.hack both original and G.U.
Patapon
Klonoa
Onimusha
Jak & Daxter
Raiden
Deathsmiles
Persona
Metal Gear (At least within my family)
Assassin's Creed (same as Metal Gear)
Resident Evil (same again)
Funny story about Metal Gear Solid. I lent it to my cousin to play and he seemed to really dig it, until he had to contact Meryl by looking for her Codec number on the back of the cd case. I think the breaking of the 4th wall severely put him off and he's not touched a MGS game since. He also has the 1st Assassin's Creed game and "just couldn't get into it", I think it's because it heavily into sci-fi rather than all assassin, all the time.