Three survey programs worth joining:
'Your Voice' is a survey panel run by AC Nielsen.
For completing surveys you will receive e-points and entry into ongoing competitions, including a $15,999 Mazda 2 every 3 months. I have been participating in 'Your Voice' for quite a while now and in the past I have traded the e-points for Coles vouchers.
'Market View' is a new survey panel run by I-View. Doing their surveys get you points that you can use to buy things from their online store (including gift vouchers)
I have just added these to the complete list of survey programs that I am recommending in 2008.