Its up to you really, there's a million choices between all the rad/fan combinations. In most cases, there is not a "right" or "wrong" way to do it, really, its about what you're looking to get most out of it.
If aesthetics are the priority, go with the fans you think will look best in your system.
If you're more worried about function, then find the best pressure-optimized fans to suit your system.
If you want silence to be a priority, then you have low-RPM options there as well.
You can even get a balance of both if it will work better in certain circumstance for one rad, but not the other. (i.e. eloops as top exhaust, typhoons as front intake)
It's your system, and about what you want or need.