We know for a fact that almost all of Armstrong's rivals over those seven Tours were doping - Zulle, Pantani, Ullrich, Basso, Botero, Hamilton, Landis, Mayo, Vinokourov, Kloden, Virenque, Beloki, Heras, Mancebo, Rumsas, Rasmussen, etc etc.
Ignoring for the moment the 6 EPO tests and working with Ferrari and all of the other evidence that points to Armstrong doping, what I'd most like to hear (and have yet to hear) is a rational explanation as to how Armstrong managed to beat all of those doping riders by an average of about 3-5 minutes (and upward of ~7 minutes) for seven straight years without doping himself.
To me, that's the most damning evidence right there. There's simply not a chance in hell that a clean rider can win a three-week Tour 7 years in a row by minutes over numerous doping rivals. None. Zero. Zip.