This question is sort of a sequel to that question.
When we want to build a WCF service which works with some kind of data, it\'s natural that we want it to be fast
Based on what I have gathered by looking at various reviews and performance benchmarks, I would choose protobuf-net as a serializer. It's just a matter of design whether it can be plugged into my service configuration. More info about that here.
Although not completely an answer to this question, jessehouwing had the best answer and I am marking it as accepted.