I went to see the Bourne Ultimatum with some friends last night.
What sets this apart from pretty much every action film I have seen is the quality of the filming and editing. It's deliberately largely done with handheld cameras, and often with shots lasting less than 1 second, especially during action scenes, which gives it a very breathless feel. You can't always see exactly what is going on during fights, but that is deliberate and it works very well. It's more like you're in the fight, or in the car crash or whatever. And then when it calms down, there will be a long, fairly still shot with little happening except the ruins of what just got destroyed, again fitting the pace.
Plotwise, the film is fairly simple. Jason Bourne tries to find out who he is by running after whoever he thinks might know. There are some clever bits, but it's the filming that really makes this a great film, and it doesn't have the kind of plot holes or cheesiness that makes Transformers, for example, so difficult to watch. Definitely worth seeing at the cinema.