I think this would work nicely with a descending list of the most completed in some sort of a table showing the completion count. It would also be nice to see which people (or where they're from) completed them as surveys are sometimes geographically exclusive.

To be honest, what I think would be more helpful is user specific lists of offers they've already completed. I think one of the biggest problems is that people try to do surveys they've already completed (or they try a different NAMED survey that's basically the exact same as one previously done). It's not always easy to spot that the survey is a duplicate, especially when it's named different and from a different offer page, so I'm betting there's a lot of redundant submissions.

I've been thinking up a lot of idea's for the survey guide thread I'm going to write up and the thought's I just mentioned are going to be on it. Hopefully I can get screenshots of different surveys from different offer sites and point out they're pretty much the same.