At this point, it does not matter whether Lance Armstrong used EPO, testosterone, or any other performance enhancing drugs. The fact that several former teammates have confessed is enough to cast doubt on all of his victories. After all, cycling is a team sport, and Armstrong would not have received the same level of support from his fellow riders had they not been doping.
I know the UCI doesn't work that way. When the grunts of a team get caught doping, they get punished while their leader goes unscathed. But that's probably wrong on their part. If the UCI really wanted to eliminate doping, they would nullify every victory that a doping rider contributed to. Teams already have their own testing regimens in place, so they know damn well when someone isn't following the rules.