Lpc2000

Assuming that I want to be able run at maximum speed, what 
oscillator/crystal should I choose?

Normally the choice is dictated by the divider for the UART, but in 
this case (from what I understand) with the prescaler you can get just 
about any baud rate you want from whatever source frequency you choose.

So if 10*6 or 20*3 or 15*4 all yield 60MHz, what factors are there 
that influence which frequency should be used?