Hi,
you named 3 architectures from Freescale and one Standard architecture (ARM). All of your list are 32-bit architectures. The best architecture is what fullfils your needs at the lowest overall cost (which includes time to market, future upgrade options, tool requirements, required budget to get started...).
There are a lot of manufacturers for ARM, there is only one for Coldfire, a couple for (very different) Power PC. If you want selection from many vendors, look at ARM. The most Standard Microcontrollers with ARM7 core you get from Philips, ST, Atmel und some more specific devices from Sharp, OKI, TI, Freescale....
So, your requirement for memory space, performance, pricing... will dictate a lot what to use.
Bob