IVE PLAYED LEFT FOR DEAD ITS REALLY FUNNNN but then again dead space has more of a story and alot more scarier so depends if you want to get scared and have a good back story get dead space but if you like havin fun online get left for dead
it depends on what you're looking for. Multiplayer and arcadey-ness is left 4 dead's forte, and a great single-player ambiance and creepiness from dead space.
im sayin u getfallout cause once you beat it(which doesn't take that long) it gets really fun so either left 4 dead or fallout. But also im not into the whole scary genre of games so whatever.
I personally haven't played Left 4 Dead yet, but when I went home to visit my parents for a few days, I got really far in Dead space, its amazing, I actually watched an animated movie of Dead space, Dead Space : Downfall. Even if you're not a fan of the game check it out, pretty cool.