Blizzard wants you to have a special appreciation for globes when fighting for Sanctuary in Diablo III. Hold these in the highest regard - they are as important as the air you breathe. Without globes you don't fight. Without globes you don't grow and advance. Without globes you don't eminate presence.
Hi! Welcome to the class! We were just talking about health refills and enemy drops. Here's a syllabus; have a seat wherever you'd like.
These globes are the core means of regenerating your health in Diablo III, and all other methods of healing support them. When you pick up a health globe, your health (and the health of any allies in your party) is restored by a fixed percentage depending on the type of globe you've grabbed.
The above quote is lifted directly from the official Diablo III website. It's a pretty straightforward approach to what resonates the classic RPG health system, with a co-op twist. No automatic regeneration...refills are dropped by slain enemies...picking up a health globe shares the health with the entire party.
Your remaining health appears as a red liquid-filled orb, which drains out as you take damage. It's not a completely unique approach, but then...unique does not always equal better.
Source: Us.blizzard.com