Third person narration is ideal for longer works featuring multiple characters, such as The Stand and Tommyknockers. God, could you imagine the Stand being told solely by one character's point of view? Ick, that'd get old mighty quick.
First person is more precise, and tells a more intimate tale. Many writers find it an easier form to work in...BUT! It is quite limiting, IMO. Say you want to write about a heroic protagonist, who is rich, beautiful, smarter than everyone else (ugh, I wouldn't, but many writers do)--to write from this character's POV ends up sounding like a bunch of bragging. This is a point I often stress to my sister, who will write in nothing but first person, but always writes about beautiful woman and rich, handsome 'captains of industry' and what not. I'm just, like, 'ugh, Gina, don't you see how arrogant it sounds? How VAIN?' (She just rolls her eyes--"at least I don't write pulpy spook stories" that expression says). Very well, to each his own, and there is indeed a market for the kind of Mary Sue/Wish fulfillment stories she writes, but you'd have to hold a gun to my head to make me write like that.
Give you two examples of this idea: take Raymond Chandler vs. Mickey Spillane. Both cats write first person detective fiction, but Chandler is considered literature, whereas Spillane is kind of childish in comparison. Mike Hammer can kick everyone's butt, make all the chicks, and brags about it the whole time. Philip Marlowe, on the other hand, gets his butt kicked more often than not, and rarely gets the girl--he usually winds up alone, bruised, and double-crossed. I can believe in Marlowe, I like the guy, whereas Hammer just sounds like one of those arrogant blow-hards you meet in a bar.
Anybody get what I'm saying?