It ain't scary. I know how you feel - I don't like horror games either. But Bioshock isn't scary. A few moments are a bit startling, but it's not scary.
It's not the most brilliant game ever made, nor was its story all that unique. It borrows a lot from existing novels and films and plays, and while there is nothing wrong about that, it will mean that if you're even modestly well-read, the game will NOT blow you away. However, I do have to say that Bioshock is the first GAME to really explore the elements of pride, freedom, individualism and free will in such depth. It is well written, and the story is absolutely worth going through. As a game, it plays modestly well, but it is excruciatingly easy. If you want a challenge, Bioshock ain't it. You simply cannot die. Well, you can, but it's like a death in multiplayer COD - you respawn instantly, close to where you die, and you lose no progress at all - so even if there's a lot of enemies, you can always wear them down through a battle of sheer attrition.
Shooting mechanics, eh, not so great. Plasmids are fun to use though. The "moral choices" that the game presents are also nothing special.
But again, the main story line is absolutely worth your time, if you happen to like stories. The art direction and the atmosphere are also pretty damn nice (if you like a good ol' 50's vibe like I do).
I would go so far as to say that the gameplay was deliberately made simple so that you could enjoy the (EDIT) game's story . Well, simple is a harsh term - the game has quite a few moves and guns and plasmids and techniques. It's just that you can choose to ignore all of it, since you quite literally cannot lose progress or be stopped. You're basically invincible except for the final boss, and that's a cakewalk anyway.
Looking back on Bioshock, I would have to say that I definitely enjoyed it, I think it was well worth the 40 or so Australian dollars I paid for it (PC version), and that I would have been happy paying full price for it. Since you're getting it rather late, you probably paid very little for it, so it's doubly worth your time.
If you're all TL

R then:
1) It's not scary. Very slightly startling at points. A tad bit depressing and gory at others. Nothing special if you've played modern video games
2) The story is quite good. It's not the most original thing out there, but it's definitely not bad. It borrows a lot from other works, but that's totally okay. Nothing is truly original anymore anyway.
3) It's super easy. That's not to say that the combat isn't fun, but it's..... not spectacular and not what the game is about.
Play it. Give it a shot. You already have it anyway.
And to all the other posts arguing about Bioshock - look, it's okay to like it or dislike it. Everyone's different. Not everyone likes every game or hates every game. For pete's sake, don't tell me you don't know the phrase "It takes all sorts". If someone doesn't like Bioshock, is it really that "shocking" (dur hur hur) to you? If someone likes it, is it a reason to get all bent out of shape?
I disliked Crysis and Heavy Rain. I liked Mass Effect 2 and Uncharted 2. I liked Half Life 2 and Bioshock. I didn't the first Left 4 Dead. I liked Portal and Black Ops. I didn't like The Witcher or Doom or Painkiller.
You can like or dislike a lot of things, children, and you know what? To each his/her own. Four frickin simple words - TO. EACH. HIS/HER. OWN. Got that? Want to write it down and put it on a post-it note so you don't forget junior?