Superbowl 36 when the Patriots won their very first championship ever. The team had been around 40+ years at that point and had been the doormat of the league for most of those years. Plus, no one gave the Patriots a chance against "the greatest show on turf" (the Rams). Going to New Orleans for a long weekend is not too shabby either.
Superbowl 39 was a close second only because the Eagles fans were the MOST obnoxious I've ever encountered. They were SO loud, SO confident, and SO in your face entering the stadium and then they were SO quiet leaving.
