Lots of rude jokes - the best of which you've seen in the trailer (the rattling off the white-trash names and the 'thunder buddies' song) - and a few cameos, including the guy who played Flash Gordon in the 1980 movie (Sam Jones) and Come Away With Me singer Norah Jones (slightly out of place).
I think what spoiled this movie for me was that I went after hearing from a couple of people that it was the funniest movie. You know what happens when your expectations are too high - they can never be fulfilled.
Funnier movies I've seen this year include American Pie: Reunion and definitely, 21 Jump Street.
Ted is okay. I wouldn't say don't go to see it. I just want to lower your expectations so you'll enjoy it a bit more than I did.