I think it really all has to do with your demographic, I think, or just how you relate to it all.
I loved Knocked Up, thought Superbad was funny, but over-hyped.
I loved 40 Year Old Virgin simply because my husband's best friend has a toy room to rival that of the movie, and when we all moved in together - an entire wing of the house was ALL TOYS. It was just ridiculous.
Needless to say, he did not laugh during the toy collection references.