I love all of them besides smash

If we're talking amount of games then Mario, but overall franchize, definitely Zelda. I've played almost all of them and been immersed and excited every time. An epic Zelda adventure wins in the end, but the pure gameplay joy of a good mario title is gold too.

It has to be Zelda. Mario has made some great things happen but for me, whenever a new mainline Zelda is released it's like take some sick days because I'll be using them to play Zelda.

Zelda.  Because my favorite genre is 3rd person action adventure.  I'm going to admit that I haven't played any of the others, but l am almost 100% sure that I wouldn't enjoy them as much as Zelda.

That gorgeus Zelda U is probably the game that's gonna make me buy a Wii U, even if I have to resell it shortly after.

EDIT:  Sorry, I forgot that I did play some Mario and Donkey Kong back in the day, in the SNES. But I'm just not into 2D platformers.