Opinion Outpost is by far the most forthright. They send a decent amount of surveys and pay through Paypal. There are different activities and payment methods, but thankfully, not so many that clog your inbox and bogus rewards like a DVD.
SurveySavvy only sends me surveys once in a blue moon. However, it is the only thing they do (no minipolls, sweepstakes, etc), and if you don’t like Paypal, I believe that they send you a check!
We all love Google, but if you ever want to trade off their service for possible money, try Swagbucks! Or if you can’t, they also offer surveys, offers, videos, and other tasks. Get paid through Paypal and a multitude of other methods.
YouGov asks about topics ranging from politics to celebrities, and I think they may influence news reports or other legitimate sources. No Paypal but they do offer gift cards from Amazon, Target, and prepaid VISAs.
You’ve probably seen their commercials! While it might be a lofty goal to earn $900 back like the lady in the ad (unless you shop exclusively online???), I’m quite pleased so far with my experience. Ebates earns a commission from sales from you, and gives part of it back!