Personally as a reviewer this is hard to say because there are several very fantastic movies this summer. If you want to see a full list of summer movies I did a hub on summer movies that you can take a look at, then decide for yourself what is the best movie of the year thus far.
I would like to say that so far this year to me the best movie is totally Transformers Revenge of the Fallen!
What is it with this Transformers 2. Its just a dumb movie about giant robots. There isn't any true depth in it. Except for the action and special effects. What's all the craze for? Michael Bay should have never done that movie, in my opinion. Bad Boys is his best movie ever! He can never top that, ever! Now you can crucify me. I've always wanted to say that.