What's so great about Stairway?

OK, in another discussion today, someone (name withheld to protect the guilty), quipped something to the effect of “Is Stairway to Heaven really that great of a song, anyway?”

In my opinion yes, it is one of the foundations of every bit of hard rock and heavy metal that has come since. But it is not my “favorite” song, nor is Led Zeppelin my “favorite” band. But I do recognize that Stairway is universally considered by seemingly the majority of rock fans and historians to be the best song ever written.

Again, I wouldn’t personally go THAT far, and I could write on and on about what I think is great about it. But I’d rather get some other viewpoints here, maybe we have some uberfans who can explain in great detail what it is exactly that makes Stairway such an enduring and powerful song that it invariably ends up at the #1 spot in pretty much every countdown of the greatest classic rock songs of all time.

So here’s your challenge, prove to the skeptics who just don’t see what’s so great about Stairway why it is indeed a great song, worthy of the reverence it is paid. Please make intelligent arguments and back them up…I did an internet search to see why Stairway was so great, and all I could find is sniping back and forth between those who had nothing more intelligent to say than “Zeppelin were gods,” and “Zeppelin sucks and you’re an idiot if you don’t see that.” I guess I’m just hoping for more analysis than emotion.

Conversely, if you can intelligently argue why it’s overrated, I welcome that viewpoint as well.