For the next few polls, I plan to focus on one console at a time so that there is no perceived or actual bias towards more popular and/or more recent systems.
The N64 poll is going to be pretty barren considering there are only 15 games on the VC.

Then again, maybe it will give me the push necessary to play Sin & Punishment (I downloaded it the day it came out and haven't played it for more than 15 minutes).
My nominees for NES games are as follows.
The Legend of Zelda - Everyone has played the more recent LoZ games, but lots of people haven't played the original. I haven't played it in years and I was never able to beat it when I was a kid. It could yield a lot of good discussion about the evolution of the series (not that it hasn't been discussed to death on the Internet already). It's one of the more meaty NES games and certainly playable today even if you don't have any prior history with it.
I think it would fantastic if we got a bunch of people to play through this together and we all agreed to avoid GameFAQS and instead swap strategies/information with each other on here. It would be like the elementary school playground all over again!
Castlevania III - The game is fan-freaking-tastistic, although having just played Super Ghouls 'n Ghosts this might not be the best choice.
Bio Miracle Bokutte Upa - I know Jonny's already played this game, but something about as weird/unique at this deserves a wider audience. Most people haven't played it so we could experience a new game together. <3
Ghosts 'n Goblins - Just kidding.
Any of the Mega Man games are fine choices, too.
I honestly didn't like River City Ransom. I never played it as a kid, and when I played it on VC a couple years ago it just didn't grab me. The combat was repetitive, the power-ups you could buy didn't tell you what they did and I quickly got bored. Then again, I was playing solo, which is definitely NOT the way to play the game. I'd be willing to give it another shot if it wins.