Any rated for 60-100g will do just fine. If you're going to heavily stock, aim for closer to 100g rated options. Light or moderate stick with 60-80g models. After that, preference is all based on price, footprint, options, etc.
I have the 150SSS on my 75g and kind of wish I would have gone a little smaller, the 6" neck is a little large for this tank size. It is a good skimmer though and always pulls out skim. I think a 110SSS would be a better pick size wise. My only user complaints about this skimmer is its tough to remove the cup for cleaing and the twist pipe for controlling water level needs to be a gate valve. Its very quiet, easy to take part to remove the pump, performs well and the 150SSS would do really well on a 100-120g tank. I do plan to heavy stock my tank so thats why I went with a larger skimmer.