Dead space 2 features a range of great UI references, from the in-game interfaces to the menu screens. But what's interesting about the Dead Space 2 UI is that it uses a fully diegetic interface. Which is basically the description of an interface that is shared by both the user and the in-game character. The term diegetic, is often used to reference music in films, where diegetic music is heard by the characters because it's played within the scene, as opposed to non-diegetic background music.
The best design element would have to be the health meter that's displayed on Isacc's back as part of his suit. It's such is a neat alternative to simply having a health meter displayed on the screen HUD. This approach to game UI is used to help immerse the user deeper into the game and story.
For more information on diegetic interfaces: Check out this great article on "Game UI Discoveries" over at Gamasutra