I've been told that all of this goes out the window if you storage is on a SAN. With fiber-attached SAN you can put all of the tempdb storage on one disk and you don't need one file per processor and balancing the sizes doesn't matter. True?

BTW, the phrase "I've been told" is the old problem of software types like me being told how to do things from hardware types. The information is sometimes valid and sometimes not relevant to what we are doing. So it goes.