And even 2 has some really fun parts like the rock climbing intro. Just watched 5 last week and it was great. So well done - love the Vienna opera scene and the scene with the prime minister. Also recently watched 4 and it is awesome, especially the first half. The ending seems to get dragged out a bit too long, but that seems to be a weakness of all of them. And 6 had so many awesome scenes incline the HALO jump, the night club bathroom fight and the car chase in Paris.
One is great nostalgia for me as it was one of the three movies I saw right before my mission, the others being Twister and Independence Day!
Also, the series is so much more enjoyable than the Bourne series. I recently watched all Bourne movies and found them to be very formulaic.