The N64 Paper Mario was basically the first RPG I played (even before Pokemon), so the game will always have a special place in my heart, I loved it as a kid and still love it now. Great story, great gameplay, great music, it's basically a masterpiece in my mind.
Then it comes The Thousand Years Door which implemented what made the first game amazing and perfected it. The gameplay is superior imo, music is amazing and story is better than the first game. A masterpiece x 2 
I have a soft spot for the first game for being my first RPG and all, so that game is my favorite in the series, but if I look at it objectively TYD is a better game imo.
Super Paper Mario was....ok. I don't hate it like a lot of people do, but I don't like it either, for me it was just a "meh" game. It doesn't live up to the expectations of the series but it's not the worst thing that ever happened like some people said...
I haven't play Sticker Star, but I haven't heard too many good things about the game. I will play it some day when I can find it very cheap.
Nintendo and PC gamer
