The Lockheed F-22 Raptor went operational today. The controversial plane will take over the air superiority mission from the venerable F-15. Critics have questioned the need for the expensive planes since likely adversaries (and especially terrorists) don't field air forces that would need to be shot down. The Air Force even tried tacking on a ground attack role.
The US has been steadily losing ground to advanced Russian designs like the Su-37. The Indian Air Force (in modified Sukhois) has already bested the USAF in exercises. It would be interesting to see how the Raptor fares. I imagine it would win handily.
The US doesn't need 400 of these units, but we do need to show the world (meaning China and Russia) that we are still numero uno.