Zelda is number one. Metroid comes next and in last Mario

Zelda!

Depends on my mood. For a quick bit of fun, Mario can't be beat. For when I'm interested in an epic adventure, Zelda's the way to go. I've distinct favorites in both series (SMB3, SM64, SMG; Zelda 1, LttP, TP), making it hard to really say I prefer one over the other.

I think it is safe to say Zelda is more popular among core gamers...

Mario for me. Love the Paper Mario series, and Sunshine was only a mild disappointment. Zelda, well, I haven't LOVED Zelda since A Link to the Past, although I did enjoy Windwaker. I'm one of the very few who didn't really enjoy Ocarina of Time/Majora's Mask =/

You're not the only one who didn't enjoy OoT, pearljammer. I also could never get into it, mostly because it's just so... lifeless. The game is plenty impressive for its time, and can be enjoyable, but most of it seems to be spent in empty environments of disproportionately huge size to Link, just running from point A to point B. Twilight Princess did a much better job of masking this reality, particularly with the extensive warping system.

I would say that Zelda games are markedly more popular amongst gamers who are willing to sit down and play for a long stretch, but I don't think it has quite the same sort of repelling factor towards casual gamers as a title like Metroid Prime 3 does. Though Zelda games are more complex than Mario games, they're still a far cry in complexity from any given Metroid.

Both!!!!!!

If your solely comparing Super Mario and the Legend Of Zelda series, I think I'd have to go with Zelda
Compare the best on each console:

SMB 3>Zelda 1
SMW<LoZ:LTTP
Super Mario 64<LoZ:OOT
Sunshine<Wind Waker
Galaxy>Twilight Princess

Gotta give it to Link

My vote goes to mario on each game you listed. I enjoy playing zelda games, but nowhere near as much as mario.

Mario 50.9
Zelda 49.1

I love them that much it was hard to decide.