Dead Space is the perfect game for me.
Atmospheric, gorgeous graphics, not too much gore, seamless animation, immersive, the ship just feels like an actual ship and repairing it is a nice concept. Voice acting and dialogue is solid enough to not be a problem.
I haven't watched Aliens or anywhere near enough sci-fi to feel this is a rip-off, the voice acting is solid and something about the animation/interface and third person camera gives it a sort of realistic feeling, like an actual sci-fi movie. The monsters are creative and the zero-g sections are lots of fun.
Definitly a better buy than the Orange Box.