I doubt there is anyone on the planet that would agree with all of the nominations, but I too have to say that Roxy Music definitely deserve their place. They may not have had as much success in the US, but they were huge and very influential here in the UK.
I don't like anything Janet Jackson did/does but I can't deny her place in music. Just because I don't like it, doesn't mean it's sh*t, it just means I don't like it. The same goes for Radiohead I have never understood the reverence surrounding them, their songs are dirgy drivel as far as I'm concerned, but they have sold more records than I ever will and influenced (for better or worse) loads of bands.
Def Leppard are one of the biggest selling rock acts. Hysteria alone sold in excess of 25 million copies worldwide and went 12x platinum in the US!
The Zombies are an odd choice I'll grant you. She's not there is a great song, but they aren't the most influential band on the list
The Cure I see no reason why they shouldn't be on the list. Again they are massively influential and have sold bucket loads of records
Having Stevie Nicks in the list is just being greedy! She is already in with Fleetwood Mac.
I think the biggest crime in the Hall of Fame is some of the exclusions; Sparks for example. Here is a band that has been constantly producing new material since 1969, have influenced loads of people and have pioneered many things that are staples now.