This list will be expanded but I will start with the top one:
BTCClicks is as the other PTC sites that I have written about in this site (such as ClixSense and NeoBux), only here what you earn are fractions of Bitcoins. You can earn extra if you upgrade your membership, which can be done with bank card or with Bitcoins.
And it also has a referral program.
I’m not sure yet which promotion I am going to put for this PTC site, but I’ll have something. It will be retroactive, so if you join before I have the promotion you will be included, and if you reached whichever threshold I set up when the promotion comes out, you will automatically get the reward.