If I could only play one game moving forward it would be Metroid, simply because it's a better series. However, if I could fund one game for WiiU, knowing the other would eventually arrive on another system, I might go for F-Zero. The series, in limbo for a decade, deserves another installment, especially with Sony shelving Wipeout.

It's scary to think we may never see a F-Zero or Wipeout game again.

Well, f zero could really benefit from the gamepad to creating tracks and even cars, and since nintendo is investing on some e-sport now, i think would fit ok on their style. Besides, fzero didn't had a chance for some time, even if their last game was well recivied.

Metroid, on the other side, i would be okay if it released along with this:
but i'm not really into this franchise, and since the last entry was not reagarded as good, i'm not confident about the direction in wich it can go.

So, for now, my bet is on fzero.

PS: i'm the only one who feels that some people don't realize that metroid is not a shooter game, and more about desolation, and some people only ask for it to try to go and compare with another futuristic shooter games like halo and destiny, instead of actually buying it and playing it?

Metroid, because Metroid...and because Metroid. But mostly because Metroid and other Metroid stuff. You Metroid what I'm saying, Metroid?

Both are extremely good series. Prime and GX were so epic. But due to the fact Metroid can actually utilize the Gamepad I'll go with Metroid (e.g., scan stuff with it, put map on it, etc). Fast paced games like F-Zero don't work with the Gamepad: no time to look at it.

Metroid of course as I don't really care that much for F-Zero

Metroid. Never been interested in F-Zero.

Metroid is much more popular and would get way more sales, so pls Retro let's go

Neithers Nintendo cares about it.

Metroid, as Nintendo doesn't seem to care for F-Zero anymore, and we're already getting FAST Racing Neo, anyway.

F-Zero because it has been a while since we have a game from that franchise and I miss a fast paced hard game like that one.
I don't like my options, but I would go with F-zero.