Re: Ice or no Ice
Ice would probably help with the filtration process a little.
I'm not entirely sure whether the water in the base helps filter out some extra nasties in the tobacco, along with cooling the smoke... By Dakingkevin23's merit, cooler water should slow down the consumption of anything undesirable as well (creative choice of words to avoid a case of the ol' "hello, irony!").
Either way, I've always used ice in every hookah I've prepared personally. I've had one or two hookahs without ice, and there's really no difference as far as taste goes; the smoke is just cooler, and thus more pleasant. Personally, I think it's a little less physically damaging on your lungs as well.
I do like the idea of the re-iceable plastic cubes though.