As for me, I LOVED Star Trek- very solid movie, and very enjoyable even if you don't know anything about it.
Terminator Salvation was VERY good, but you have to be familiar with the series to really enjoy it.
UP was a fantastic movie. One of the best Pixar movies, in my opinion.
Night at the Museum was pretty entertaining.
Away we go is an overlooked movie that is definitely worth watching.
Public Enemies was very solid.
All of these movies were entertaining to watch in varying degrees. I don't think you could go wrong with them, with the exception of Terminator. Like I said, it is very dependent on you seeing the other movies, and its also rather dark.
Movies I have not seen:
Ice Age, The Hangover, Transformers 2, all of the romantic comedies (the proposal, etc), Bruno
Movies that you must avoid at all costs:
Land of the Lost: Nothing particularly horrible, but it was a waste of 90 minutes or so. Not particularly funny and a big opportunity was missed to make something great.
Year One: I walked out of the theater. It was simply one of the worst movies I have ever seen (the part I did see, that is).
Taking of Pelham 123. Just a dumb movie. Not worth the time.