It has everything - great acting (Depp must get an oscar for his performance), great story, action, lots of humor and generally tons of fun. The scenes range from hillarious, to full-blown action (haven't seen a good sword fight since LOTR TTT), to surprising turns in the plot, to even some horror.
How often do you see a movie, and really-really don't want it to end (even if it lasts 2.25 hours) ? This is one of those movies.
After seeing it, I looked for some web reviews, and most are very positive, even the ones at IMDB.
Go see it, you won't regret it !
P.S: As I'm reading Moby Dick at the moment, it was really cool to see a movie with all those ships and generally old-fashioned sea action.