My current survival world is my first world that I've actively played since I got the game, so naturally, I have the most diamonds right now (300 diamonds). I still don't know if I want to use diamond armor.
currently in my ever expanding world that ive had since alpha i have 5 stacks of diamond blocks and 8 diamonds so that is Thirty-two thousand-two hundred-eight diamonds, I have a mine thats like 20 x 20 chunks big and another thats 30x 30 chunks which is about
Me and my friend made this local server one time round his house and we found about 40 diamonds in a single cave system. We got bored of finding them after a while, at the start it was like "OMFG DIAMONDS!!!" then at the end it was like "meh another diamond here".
I currently have over a stack (maybe 75?) diamonds on my SMP world right now, and almost two sets of diamond armor, though I've never worn it. Just enchanting it every time I get to a high level to get ready to kill the dragon.