You assume that "ia32e" is pre-destined for success, based on what? A couple of slides? Intel hasn't even spoken yet.
BTW, your choice #3 would be considered a victory and vindication for AMD64, as it would survive as the lowest-common-denominator.
And I wouldn't knock 3dNow!, it's just another in a long line of AMD innovations that Intel has been forced to respond to:
MM extensions
DDR vs. Rambus
Copper Interconnect
And now 64-bit extensions, whatever they turn out to be...
BTW If they are incompatible, don't they have some software to write? Cause I haven't heard diddly about CT software yet, i.e. Linux.
What will be Intel's next about-face? SOI?
fpg