I saw it last night. A few thoughts:
1) It was a great movie that I thoroughly enjoyed. It was funny throughout without being overly ridiculous and without relying on gross out humor. It is largely very intelligent, clever comedy that is reliant on outstanding writing. There is a fair amount of drug humor, so if that isn't your thing - be forewarned.
2) It was WAY more of a romantic comedy than I expected. This might be the best date movie of the year.
3) Judd Apatow really wants to make sentimental, wholesome movies that are also quite funny. Knocked Up is like a more sensitive version of Wedding Crashers or 40 Year Old Virgin. Similar comedy style, but more attentive to the love story and the real emotions that go along with it.
4) Paul Rudd is fantastic.
Overall, I thought it was extremely well done. Recommeded.