It depends on what you want to keep. If you want to keep softies mainly, the turn over can be as low as 10 times. The flow from a return pump would be a part of that. The rest comes from either powerheads or a closed loop system. You will need a lot more flow in total if you would like to keep SPS's, but the return pump can be the same size.
I have a Mag Drive 12 on my 120. A lot of people use Mag Drive 7 or 9 for 75 to 90 gallon tank.
I prefer an Eheim pump because it's silent and runs cool (I love the ones on my planted tank and a calcium reactor.) Mag Drives are reliable but hot and noisy. I hear that Ocean Runner pumps by Aqua Medic are great like Eheim pumps but cheaper than an Eheim.
Tomoko