Wolfgang's Vault (Bill Graham's live concert archive) has been around for awhile in various forms, but now it's online in all of its glory.
I've spent this morning listening to Led Zepplin at Fillmore West from April 27, 1969. Here's the playlist:
But being able to listen to Led Zepplin from 37 years ago is a damn good thing. All in all, I'd argue (and have argued) that we are way better off now.