I have been doing surveys online for over 5 years now, during that time I have been a member of many survey panels and have been paid numerous times.
In my opinion 2 sites stand out above the rest, they being:
http://www.survey-head.com - pays by paypal
Paid to do surveys, no need to complete other offers, just do a survey when it is available and get paid for it.
http://www.cashcratesurveys.com - pays by check or direct deposit
Paid to complete offers and surveys site, has slightly more earning opportunities but is a little more involved.
Both are easy to use and provide the opportunity to easily make an extra $100 to $200 per month, if nothing else they are worth having a look at to see what you think
Good luck with your search.