I think "Ok Computer" should be the number 1 album of the '90. "Nevermind" is a very important album that change the music in the '90 like "Nevermind the bullocks" did in the '70 (with much more strenght). But like the latter, it's seems tied to his era while "Ok Computer" trascend the time and it is still modern and beautiful.
Maybe according to Rolling Stone, but when I hear todays music, the bands that are really good and acclaimed as such obviously have some Radiohead influence. Nirvana inspired a whole bunch of bands to make pretty bad music. That's not Nirvana's fault, but when considering influence you have to look at what they were actually influencing.
It's really tough to compare these two though because they are only the same in the fact they were groundbreaking albums. To me, Radiohead will be a classic in the vein of Sgt. Peppers/Pet Sounds which have universal acclaim. Nevermind might be more like a Zeppelin II/The Wall and become a classic rock radio station staple.
I like OK Computer more, but again we're comparing two completely different albums that came out at opposite ends of the 90's.
Yeah, Nirvana did have a big part in the shape of the 90's sound. But, that really isn't influence. Influence comes into play in the next generation from the kids who listened to the music and went to the shows. Grunge just kind of shaped the scene. All of the bands that became big were the same kind of sound because that's what was hot and therefore they were signed and were able to get records marketed.