I was never a die hard Halo fan, but I DID give majority of the games a try. After playing Reach as much as I have so far, I have to say this is the best Halo game to date. I wasn't too keen on the previous games other than the first one, but Reach definitely surprised me. I've completed the campaign and found it somewhat hard to put down the multiplayer because something keeps pulling me in again. It's worth checking out!
I have to say that the whole storyline, the game play, the levels, the content, and the difficulty of the game makes Halo Reach the most awesome and fun game that I have ever played! Really, this is a must if you just mildly like the Halo franchise!