Does someone know what they are referring to about "commodity x86 servers"? Does this mean Core2 or Opterons? as opposed to Dunnington, Tigertons, or Itaniums?
The term "commodity x86" is somewhat redundant, since almost all x86 machines are commodity (in the sense that a server from Dell and an equivalent server from, say, HP are effectively interchangeable).
It is rumored that Google chooses processors based on performance/TCO, which would exclude the crazy expensive ones.