The only one that is part of the Clerks Family - http://www.socialclerks.com
I would highly recommend www.YouPlusLike.com
SocialSmash, It's pretty easy to earn coins and we have just released a feature where you can export your coins to coupons that you can sell here on SeoClerks and on other webistes.
For me it's youlikehits.com
Its Simply Hackable
it depends on what you need, for example i like twitclub.com for twitter etc etc
for me youlikehits.com. but not the interface.
socialclerks.com and youlikehits.com
www.likemefast.netwww.plusonespro.com Very good sites!!