Help requested with FIR/IIR filters please

I understand, that input sampling rate is one of the few clear specifications (200 MSPS). Downsampling seems to be an obvious first step. But input frequency content and intended filter characteristic must be known to decide about a suitable decimation filter. I guess, that a CIC filter (order and downsampling factor depend on...) is an economic way. After downsampling a FIR filter gets much more handy, but IIR is an option as well. The latter is preferable for lower resource count, if only basic filter specifications have to be met.