It depends on your definition of 'love': Love between lovers? Between family-members? Or friends?
In case of 'between lovers' I would agree with the others and say to love is more important than be loved. You are only able to receive love if you are able to give love - that's what makes it so important 'to love'.
In case of family members it is definitely more important to be loved. Once scientists made an experiment with a baby: they left it all alone in a room for days and took only care about the babies physical good. They ignored completely the emotional good, so the baby didn't receive any hugs, strokes et cetera. What happened? The baby died. So it is scientifically proven people - especially children - do need love to survive.
In case of friends it is equal to be loved and to love (each other). That's the base of any friendship: to give and to receive.
But regarded in general, there is a great quote:
"To love is nothing.
To be loved is something.
To love and be loved is everything." (Unknown)
Sure, in case of lovers-love it hurts if your love is not returned. But that's it: it 'just' hurts - it doesn't kill you (excluded somebody can't handle the pain and commit suicide - but that's another story)!
I think the hierarchy of the quote above applies the most to a humans life (although I guess it applies to any animals life - but that's another story, too ;-)).
Imagine nobody loved you: no friend, to family member, no lover, no pet - would you survive on the long term? I think anybody would end up like the baby in the experiment above: sooner or later dead. Everybody needs somebody who cares about him (even if you think you don't want anybody to care about you - you do want! ;)).
So, regarded from the perspective of 'importance' - and regarded just to the two options in the question ('love' & 'be loved'), the answer is: To be loved is more important than to love.
But the ideal case is - and remains: To love and be loved in the same way.