When you think about them, there are many not just good, but great wedding movies.  

For me, "Wedding Crashers" battles "The Hangover" for the all time best.   "The Wedding Singer" is also very entertaining, as is "My Big Fat Greek Wedding."   If you like a different type of story, you might vote for "The Princess Bride," or "My Best Friend's Wedding."

"Father Of The Bride" would also get an honorable mention as a good wedding movie.  There are no doubt some that I did not mention, please feel free to add your suggestion to the list.