Diablo 3 Gameplay Overview:
Diablo 3 Potions:
Diablo 3 will introduce new pickup items like 'health orbs' to easily replenish your health. This decision was made to keep the action more continuous and make the game easier to play. Only red health orbs have been seen so far in Diablo 3 demo gameplay, it's not known if 'mana orbs' or other pickup items will be available.
Don't worry though, the 'orbs' are not here to replace potions.
Diablo 3 Gems and Runes:
Because they were so popular when introduced first in Diablo 2, Gems, Jewels and Runes will be available in Diablo3 as well. That also means socketed items will also return.