I would sell it without question.
My interest in the NES and its library are minimal and when I did actually collect for it, it was my most uninspired collection in regards to my excitement for amassing more games on it. Don't get me wrong, I had some really good games for it and still do, but the NES is a console I never owned until much later after its heyday, and even then I only had a few games for it. I didn't grow up with it either so I have no nostalgia for it.
Owning the most expensive and sought after title for the console would mean very little to me and its true importantance would come in the amount of money I'd get from it which I'd put towards a house or something like that. There is also the possibility that I'd hold onto it for a while in hopes that it would become the video game equivilant of Action Comics #1 and be worth hundreds of thousands or even above a million in a decade or two.