I know it has gotten more negative reviews than positive ones, but I personally really enjoyed Pirates. It's a high quality popcorn movie, and it doesn't aspire to be any more than that. It is a touch long in parts, I'll grant ... could've stood a bit of trimming here and there, but just go to the bathroom before you start, and you'll be fine. Not to sound like your mother, but you should be doing that anyway when you go to the movies. The running time of 150 minutes + watching all that moving water ... I'm not going to finish that thought.
Anyway, it has cannibals, pirates in giant wheels like gerbils, great special effects, swordplay, Johnny Depp in eyeliner, a giant cephalopod, ghost ships, and a fun little throwaway bit at the end of the credits. I had fun. Was I intellectually enriched by it? No. Was I entertained? Yes, and I can be a snob about light movies, so that's saying a little something (I was wholly underwhelmed by The Mummy for example, and I absolutely hated the steaming pile of tripe that was The Chronicles of Riddick).
Bottom line: if you're looking for something pretty and brainless with some charm and laughs, Pirates will probably fit the bill nicely. It feels like an amusement park ride waiting to happen, but I didn't mind that. Just be sure to use the restroom before you partake.