Heidi, I think the best pair of ribbon scissors you can find are any that you can manage to save just for ribbon and/or fabric. I have a large pair of Fiskars I keep hidden in my sewing basket. That said, I have a small pair of Fiskars snips in my stamping tote that I'm not as careful with, and I think they work well too.
ETA : I just went and tested a few pairs, I think mine are these Fiskars micro tip
. I bought them for detail paper cutting but I just tried them on ribbon and they were fine.
I also have spring loaded Fiskars which it looks like they are calling Easy Action that I use for cutting paper all of the time, but they worked on the ribbon too. You really don't need spring loaded for trimming ribbon though, so I would go with the pair I linked above. Mine are 5 inches long over all. The blade is approximately two inches long. The Fiskars site shows them being used on fabric.
Sorry it has taken me so long to answer. I was on vacation.