Maybe I do miss something, but I cannot understand what this thread is for. Just use the crystal frequency which is best suited for your application. If it's 12MHz, then use it. If it's 11.0592MHz, then use it. If it's 22.184MHz, then use it. Where's the problem?

Do you think that I use a 11.0592MHz only because all others do use it? No. I use what is needed, what is best suited for my application. I often use 7.3728MHz, when in a mixed analog/digital application very low noise is needed. 7.3728MHz gives me both, low noise and 19200Baud.

So, why all this excitement??

Kai