Contador could very well eclipse Armstrong's record for wins; he's that good.
The rivalry will be between Contador and Andy Schleck.
Unlikely. If winning more than 5 was anything other than extremely difficult, it would have been done more than once. Remember Indurain? He was as dominant as you can be, but 5 years is a long time to be the best. When his time was up, it was up, just like many before him. A cyclist's prime seems to be about 5 years, no matter how old they are when the reach it. That's what makes Armstrong's record so amazing. That he seem to still be a near dominant climber after three years of is incredible.
I think Lance's chances of beating Cantador again are very slim, based simply on age, but the chance of somebody else doing it in the next 5 years is very great.
Remember too that the over all result would have been much closer if the two hadn't been team mates. Twice Lance dropped back a bit in mountain top finishes, and of course he never attacked Contador. Both times he finished behind him, he probably wouldn't have if he were on a rival team of Contador. But unless he can somehow rebuild his time trial prowess, he'll never catch him. And time is against him.