Funny you should mention that stage (Luz Ardiden, 2003). We were at the finish line that day, perched on a cliff with a view of the finish line immediately to our left and, down below, the last 4 or so switch backs towards the finish. The actual finish was about 100 feet from the base of a chair lift at the ski station, and the road was the usual 10% grade up the last few kilometers. We watched the take down on the TV monitors and, along with the 1000's of others, could not believe what unfolded next. When Lance appeared out of the fog, it was a like nothing I have ever seen before or since. The ONLY word that applies is "possessed." We had ridden up the same road two hours earlier, and there is simply no way to account for the speed that he was able to summon.
I am realistic about the use of performance enhancing drugs, and clearly is an issue in virutally all sports. I don't think Lance is doing it, though, and would also be utterly disallusioned if it ever turns out that his performances were based on some magic potion. Evidence is pretty strong that he is completely clean, though. An interesting study was just published about him by the American Physiological Society as a result of a long term study that tracked his performance over the years and seems quite clear on the ped front. Here is a link to a release about the study:http://www4.eurekalert.org/pub_releases/2005-06/aps-lat061305.php
On the other hand, after doing just a few of the climbs they do, any use of drugs is highly understandable, at least in my mind.