Fighter jets

When the Wright Brothers succeeded in flying their 'heavier than air' machine at Kitty Hawk way back in 1903, everyone thought it was just a toy. However, within a decade there were hundreds of such machines flying and soon it became a common sight to see flying machines dotting the skies; and they were covering longer distances.
Still, flying was only a hobby and some people who were passionate about flying either purchased or built and virtually lived in their own aircrafts. The only way they could make a living was by flying their airplanes, so they started giving "joy rides" to interested people to earn enough to maintain their machines and a square meal a day. When there were no takers for joy rides, they would demonstrate their aerobatic skills like flying the "loop" or flying upside down and a variety of other stunts, near village fairs. These pioneers were known as "barnstormers ".

The possibilities were really seen only when Charles Lindbergh crossed the Atlantic Ocean flying "solo" from New York to Paris in the thirties, in his single engined airplane christened SPIRIT OF ST.LOUIS. Soon the World War began and that was the time when massive development took place in the field of aviation. Germans were improving their aircrafts by the day competing with USA and England.
The British fighter aircrafts "Spitfires" and the German "Messer schmits" are legends even to this day.
Larger aircrafts were built to carry more people and more cargo. Mail that was ferried by road and rail was sent by air, bringing forth the now popular "air mail" service. Some businessmen and Industrialists started calling those barnstormers asking for a lift to some place as they found it was faster than going by train or car, and it gave them that extra prestige.
Thus, the advent of 'air taxis' was born.
Slowly but surely, the world realized that airplanes were not toys, and that they would revolutionize the way people traveled. The world became smaller, and aviation was taken up seriously resulting in development of larger Airliners, invention of the Jet engine, breaking of the "sound barrier" (traveling faster than sound), and even space travel, all within a century after the first ever heavier than air machine flew!The F-22 Fighter Plane (Which started life as the Advanced Tactical Fighter {ATF} and later became the Air Dominance Fighter {ADF}) and the Typhoon were programs started in the early 80's. The F-22 is intended to replace the F-15C/D While the Euro fighter plane is intended to replace a whole plethora of aircraft.
The JSF (Joint Strike Fighter) is a replacement for aircraft types such as the Harrier (VSTOL variant slated for the USMC; Britain), the F-16 (CTOL Variant for the USAF) and the F/A-18C/D (Naval Variant for the USN).

While the Jury is still out on the JSF (As far as I am concerned) I think the F-22 has turned into one of those "Projects that won't die" like the M2/M3 Bradley. The US Government has spent so much money on it that they can't afford to buy it.
Do we need it? That question is already moot. We are getting it whether we "need" it or not. I think, however, that the F-22 may be the last manned fighter to be deployed. The focus will, IMHO, switch to highly capable UCAVs...
From a military perspective, yes. What will stop these European countries from selling this aircraft to any country that wants it? What will stop members of the design team from selling plans to other countries? It is possible that our aircraft will infact have to fly against the euro fighter.

Keep in mind, there was a time when Iraq was our ally (of sorts). Just because someone is my ally today does not mean they will be tomorrow. If I'm putting you in a hunk of metal that for all intents and purposes is one large explosive. That you will have to fly faster than the speed of sound while being fired at.... call me crazy, but I think you would like to be sitting in the most technologically advanced thing you could get your hands on.
Being on the cutting edge of military advancement doesn't come cheap or easy. But the most powerful country in the world is ALWAYS the country with the most powerful military. You can't very well impose your will if you... can't impose your will.
Our military isn't just judged based upon its ability to fight those we will likely have to in the near future. But, everything out there. including our own weapons.

A lot of Russian/European Fighter planes are at par or has exceeded the F-15E's capability. This puts the US at a disadvantage. Besides, F-15 will be at least 25+ years old. For a military that's taking the fight into the OPFOR's own backyard, the US has to dominate its battle space. And that means having an Air Superiority to operate with impunity.
Sure, it's expensive. But whoever said that Air Superiority was cheap? If you looked back into the 70s when the F-15 was still in its R&D phases lawmakers said the same damn thing: "that plane's too expensive!" And now, we got hundreds of them.

The F-22 may be the single biggest waste of money since the B-1. Large, heavy, bad E-M (energy-maneuverability) ratings it simple is not a good air plane. Instead of being based on the E-M theory like the F-15 and 16 were it has instead reverted back to the bigger-higher-faster doctrine. It simply puts to many gizmos into a plan that doesn't need it. The E-M theory proved that the lighter the plane the better it will be able to maneuver, the F-22 is one of the heaviest planes designed.
It also has far surpassed its budget and its cost per plane is simply unacceptable. By the time the air force has enough money to replace its fleet with these flying boxes they will be long obsolet.