"clock speeds from 1.6ghz to 3.06ghz....is this a true reflection of performance? are they comparable or does fsb and cache come into it?"
Processor design comes into it a lot - that's why AMD processors tend to do more for a given clock speed. Not all Pentiums can be compared on the basis of clock speed either. And remember AMD "numbers" are not clock speeds at all.
Cache comes into it a lot - more cache = higher performance.
In a laptop I recommend only buying a "mobile" rated chip - they tend to perform better at a given clock speed - run cooler - and have superior power saving characteristics.