the best is bidvertiser because they pay now through paypal and the minimum payout is $10 for paypal...
just wann say that if u are a publisher from india then opt for adsense....widgetbuck is not for publisher in india....they dont have proper ads at all.... in my site i had widget bucks for 2 weeks and not a single click where my adsense was getting atleast 2-3 click but widgetbucks didnt get any and also the image ad didnt change at all.was the same for the whole 2 week period
WB pays better if your visitors come from US/CA mainly. Otherwise, use Adsense. You could combine them, also.
It depends....some sites work better with WidgetBucks and some work better with Adsense...try both of them and you'll know which one works better for you.
This is what I have retrieved from my records: http://www.widgetbucks.com/ <-- Paypal - contextual widgets (bad reputation)