I found this thread doing a search for finding the most diamonds.
I have found at least 106 diamonds in one mine so far, but it is a very big parallel branch type of mine, like a multi-floor Hotel. Before this, I have never found very many diamonds, like less than a dozen in any world before, where I had to use the 'give' cheat, but here this has given me about 106 diamonds in the past month.
Geoffr524 in Game.
In my technic world I have around 8 stacks of diamonds, with an extra 3 stacks of aeternalis fuel, which is worth the same as diamonds.
In my best vanilla world I have around a half stack of diamonds.
I am just using vanilla minecraft single player, with Inventory Tweaks.
Not using any mods or fortunes on the iron picaxes, just crafting them, then the mines are up to 3 blocks high, after a couple blocks in.
I can't decide whether to try Bukkit, tekkit, or FTB.
Since this screenshot, I have made the Mine huge.
Thinking of renting a multiplayer.
On the server I play on, I have 36 diamond blocks, 4-6 loose (I forget exactly). A full set of tools & armour, as well as a full spare set of everything in a chest. I've burned through a few diamond tools & armour pieces too, but I wouldn't count those towards my total.
I found 57 diamonds in my old world created on 1.3. That was when enchanting was MONTHS away from being added. The world got corrupted, so yeah. I feel like a noob when I see people get 126 diamonds in their worlds and they still have the world.