It's not the evil that the GOP makes you believe. It only ensures that Barack Obama can actually implement his agenda. Tax cut for the middle class as opposed to the wealthy, commonsense healthcare, S-CHIP, etc.
The GOP can fillibuster any of this. Just this year, they initiated 94 fillibusters. All a supermajority does is ensure the GOP can't derail the agenda that Obama has laid out--which is why America has overwhelmingly supported him to begin with.