JayBonci's writeup is slightly inaccurate on a couple points: not only can you no longer gamble for uniques, the unique drop order has been completley abolished. It is no longer necessary, or even beneficial, to have Manald Heal and/or Nagelring in your attempt to obtain a Stone.

In fact, the restriction on dropping uniques already in the game has also been removed, so you can get a Stone even if you're already wearing one. Also, the higher monster levels introduced in the 1.08 patch have been revoked serverside. Regardless, everything in Hell is at least L50, which is above a Stone's iLevel.

The best way to get one now is "quest and beat many hard monsters to progress your way there" -- oops, no. By that, I mean "kill Mephisto over and over again until he coughs one up." Rares and uniques are, if anything, EASIER to attain now because bosses drop them frequently, regardless of difficulty or number of players.

A few days of casual playing under the 1.08 patch has already gained me an Eye, two Venomwards, three Steelclashes, two Skewers, an Azurewrath, and another half dozen worthless uniques, as well as maybe a hundred other set/rare items (including several very nice rings). All this has been gained with a sorceress with maxed Teleport, teleporting around the Durance of Hate and using Static Field to take out Meph game after game, in combination with teleporting around the Sewers/Arcane Sanctuary/Tal Rasha's Tomb/Maggot Lair and popping chests/killing Duriel.