I also have used Synovate Global Opinion Panels, which is now I-Say by Ipsos. They send you surveys pretty frequently and the points you accumulate can turn into actual money! You can receive an actual check from them, or choose to redeem for a gift card. I haven’t cashed out with them since they changed into the new system, just because I’ve really stopped taking the surveys because I’m lazy 🙂 Here’s the link: http://i-say.com/Rewards/RewardsProgram/tabid/203/language/en-US/Default.aspx
If you are looking for highest paying surveys, then you must join Harris Poll Online survey panel. Harris Poll Online is a well known market research company and has been in business for more than 50 years. Once you join Harris Poll Online you will have opportunity to participate in paid online surveys, focus group studies and paid product testing opportunities.