Keith, kpf, the option repricing has been known for the better part of a year now. It is a very minor dilution and the effect (if any) would have been priced in a long time ago.
Today's price movement has more to do with the usual fear/greed aspect of this stock meeting last night's Intel announcement. There is still a substantial monied interest which believes that any AMD advantage is temporary and illusory, and that Intel can step in to quash AMD whenever it wants. These people probably have themselves convinced that next week's Prescott launch will release an incompatible x86-64.
When God gave out brains, they thought he said trains, and got a loco.