I feel ashamed to say it, but I've only heard 4 or 5 Nirvana songs. They were all good though.
As for Radiohead, I've borrowed 2 cds of theirs, and both of 'em schtunk worse than a chili-eatin 2 yr old with the runs. I've heard lots of ppl rave about em in the past, so I donno maybe I just got their 2 most craptacular cds, or I just happened to skip their good songs.
So, Nirvana wins