Games are ranked from best to worst.

1.) Halo 2

Halo 2 comes first. For the mystery, atmosphere, and "epic" music. You play both in the Covenant side, as the Arbiter, and on the human side as the Master Chief. The Flood were actually close to horrifying, but not close enough. Sgt. Johnson is the only hilarious character and makes the most jokes in this game, but appears too few times in this game. Gameplay was also fun with dual wielding, boarding and all the other new things added into the game. Halo 2 is the game with the biggest additions to the series.

2.) Halo Combat Evolved

Halo CE comes close to second. Not only was Sgt. Johnson hilarious, but Master Chief and Cortana were, too. Problem is, hilarious parts seldom happen and Sgt Johnson is a minor character. The game had great atmosphere and music. Again, the music was great. Gameplay ws mostly slow-paced compared to other shooters at the time, but was still fun. The game relies a bit on nostalgia to be enjoyable, though.

3.) Halo 3

Halo 3 goes at third. Epic music, epic gameplay, epic battles. Everything epic. Mystery was no longer felt and atmosphere was close to none.  But the gameplay made me come back for more and it really did feel like an "epic" conclusion. The colorful surroundings helped make it feel like a "glorious" victory. The reunion of Master Chief and Cortana is only heartfelt if players played the first two Halo games.

4.) Halo 3 ODST

ODST goes VERY close to third (In fact, it almost ties with Halo 3). For all its mystery, "noire" vibe, lonely feel, great atmosphere, ambient jazz music, voice acting, fun gameplay, it's (sort-of) open world Mombassa Streets, great, badass and well developed characters with charm and constant humor.

5.) Halo Reach

Halo Reach goes at fifth. Voice acting was average. Story was well planned out, but characters are flat, boring and you don't get to care for them much. Forge was improved a lot. Despite all of the problems in the campaign's story, the sequences were very fun and very well planned, so there was a reason to play the campaign again.

6.) Halo 4

Halo 4 goes last at sixth. Believe me, the story was very thrilling in comparison to Halo 3 and Reach, but the replayability was close to none. There was little reason to come back and play the campaign again. The gameplay could not hold a candle to Bungie's efforts in previous entries in the Halo series. The music was great, but just felt like I was listening to music from just about every movie I watched. Not Halo music.

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Halo Wars

Halo Wars cannot be compared to the rest of the Halo games, as it is, in fact, an RTS game. However, if all the games were judged on solely story alone, Halo Wars would easily come in at last. The story was uninteresting and unbelievable. However, the game was fun and is the best Console RTS effort I've ever played. Granted it can't stand against PC RTS games such as StarCraft, but it was quite good. The controls really felt natural for the controller. Music was also great and really captured the feel of Halo while staying to the regular RTS relaxing style of music.