At nearly 72 years of age, Superman is without a doubt one of the most popular superheroes ever created. Now, for a character as old as he is, Superman has been revamped, retold and re-cast many a number of times. For the most part, nearly every generation has had an actor they have identified with as its Man of Steel.
Kirk Alyn was the first man to ever don the tights and cape in live action. He played the man of steel in a film serial that consisted of 15 episodes. He is also, so far, the only Superman that has ever lived into old age.
George Reeves was second in 1950. He was cast as Superman in "Superman and the Mole Men" in 1951 and then as Superman in the television series titled "The Adventures of Superman" (1951-1958). He went on to guest star on the television show 'I love Lucy' as Superman once more before his death. George was the face of Superman for the 50s and 60s.
Then came the man who has been called "The greatest live action Superman to date". Christopher Reeve was the next Superman. He was cast fresh out of school to play the role of Superman. He played the character of Superman in the most live action productions (Superman 1978, Superman 2, Superman 3 and Superman 4). Reeve played the character of SUPERMAN (pay attention, folks) longer than any other. He is still considered the face of the character over 30 years later. He was the Superman of the '80s and, for those who were alive to see his portrayal in 1978, he is still considered Superman. After nine years of suffering through quadriplegia, Christopher Reeve passed away on October 10th, 2004.
Then came the '90s and a new Superman was needed. Dean Cain was the next Superman in the television series "Lois and Clark; The New Adventures of Superman." Cain played Superman for four years and was the Superman of the 90's. He shared this honor with Tim Daly who voiced the character in "Superman the Animates Series" and "The New Adventures of Batman and Superman." He never donned the suit and cape.
The most modern incarnation of Superman:
On September 11, 2001, America suffered the greatest tragedy in its history. At this point in time, America needed its greatest hero to draw strength from once more. Coincidentally, DC and WB released a pilot for their newest Superman series which would follow a young Clark Kent as he made his journey through high school into becoming the man he was destined to be.
"Smallville" debuted and starred Tom Welling as a young Clark Kent. Welling has been the tenured Clark Kent. He's played the character longer than any other man. He was anointed the Superman of our generation by the last two 'Supermen.' He was even approached to star in the soon canceled Superman Flyby.
In 2004, Bryan Singer became the next Superman director. He started his search for a Superman looking to cast a relative unknown and found Brandon Routh. Routh was chosen solely based on his eerie resemblance to Christopher Reeve and the reboot turned into a continuity of the Donner Superman story.
Now, since every generation has a Superman, who is the Superman of the 2000s?
Like the title says, EASY.
This is one of the most heated debates of all on this site. Some people consider Routh as Superman, because...I don't know why, but they do. Others consider Welling Superman because he's played the role of Clark Kent longer than any other. All in all, I'll give my choice whom I consider Superman and why I consider him as the definitive and undisputed Superman of the 2000s.
The Superman of the 2000s is Tom Welling.
If you disagree, it's probably because you saw Reeve as Superman in 1978 and think Routh is Superman because he smiled and posed and he looked just so Reeve-like in "Superman Returns."
... I see it too.
He is not the Superman of THIS generation just because he looks like Chris. He can be Superman of 1980 part 2, but NOT the 2000's because Welling had already been crowned. I've asked nearly 100 people whom they considered Superman in my college and Welling was the only name mentioned with the exception of a few Dean Cains. When I saw "Superman Returns" all I could see was this:

It was part of the reason why I didn't watch "Superman Returns" more than once in the theater...and the movie was boring! As "Smallville" comes to an end, I am excited to see that WB has not yet given up on the Superman franchise. I wish Tom Welling the best of luck in his post Clark Kent career, but I know that on the final episode of "Smallville" when Tom finally wears the iconic suit, it will be the coronation of a Superman. The true Superman of the 2000's. I may not want him as Superman in "Man of Steel," but I can't deny that he kept my love for Superman going to this day. He was a hero in a time when we needed him the most.