I always thought Halo is just fps zomg owning noobs game..Recently,I have been listening Halo theme music these past months every day..I get the feeling that the game has kind of happy, sad,adventure, epic story. But I have only played Halo 1 and I don't remember anything from the story..So now since Halo Reach is coming, I think I could do marathon of Halo 1 and 2 on pc,  Halo 3,Odst and Reach on Xbox 360 (I would need to buy it or get one from my friend).

But is the story REALLY good?Or more like "Call of duty good" kinda story?

no, but it seemed like the story was absent to me.

The story is excellent, definately deeper than the usual games in the FPS genre.  I would recommend checking out the book Fall Of Reach too, gives a huge amount of backstory not covered in the games.  In fact all the books really do emphasize how huge the scope of the Halo universe is outside of the games.  I doubt you have time though to complete all the Halo games and start Reach on launch day but it probably is worth catching up on the story.  For the record you could skip ODST as it's not that important in the story arch for Halo 1-3 and Reach.

Halo's story is definitely more sophisticated than most FPSes, but it's still ass. Just get Reach and you'll be fine.

If you like playing FPS games for campaign, Halo won't dissappoint by a long shot.  The story is very very good compared to pretty much all other FPS campaigns save for the likes of Half Life and maybe a few others.

It's typical sci-fi, nothing too special, but decent for a FPS. I did really enjoy the Fall of Reach book, but that's really what took place BEFORE the first Halo.

It's basically a prequel that leads into Halo 1.

The story is brilliant, sadly the storytelling in the game is lacking in some places.

Oh and better play Reach first then lol it leads exactly to the place where Halo CE starts (that's what a Bungie dev said at least)

Also try to get you hands on a cheap copy of Halo 2 for Xbox and play it on your 360. The PC port really isn't very good.

Halo's story is FAR superior to the average FPS campaign.  

You can actually start with Halo Reach though since chronologically it takes place before any of the other Halo games.