There are a few sites around which compare deals or aggregate all the latest deals company offerings in one place..
Sometimes, it can be a bit overwhelming getting all the mail shots from Groupon, KGB, D2 etc etc..
I've started looking at which appears to be quite good. Each day, they feature a deal of the day which brings you something special. they've got a reviewthedeals forum which is trying to get people to write reviews for their deals. I hope that one grows, as there appear to be varying experiences with deals vouchers. Give them a go if you buy a deal...write a review.