Very much so, though its first installment is by far the best.
Halo CE is hands down my favorite game of all time. It's narrative is simple, effective, and mind-blowingly well-executed; the campaign integrates sound, visuals, and gameplay in a brilliantly paced and told story with a solid introduction, an epic build-up, a terrifying reversal, and a very fitting resolution. It also has great gameplay, a very good multiplayer map selection, and extremely fun, if quirky, AI.
This having been said, while I very much enjoy the rest of the series, there are just so many missed opportunities and strange/odd design decisions everywhere. And while Bungie never wrote a fully functioning and complete narrative after Halo 1 (except for arguably ODST), at least the script writers still kind of knew what they were doing in Halo 2; I'm not sure the same could be said for the games after that.
Halo 3 Marine: "MA'AM, SQUAD LEADERS ARE REQUESTING A RALLY POINT. WHERE SHOULD THEY GO?"
Miranda Keyes: "TO WAR."
x.x
(Although, the Gravemind suffered far more than any other character in the transition from Halo 2 to Halo 3. He went from being an interesting triffid who speaks calmly in trochaic heptameter to just some dude who likes to scream random crap a lot while getting in the way of the interface.)