(OPINION OPINION OPINION)
The first real online shooter experience I had was with Halo: Combat Evolved (Ok the first one was Doom, but I was like 5 and just kinda ran around and didn't shoot anything, plus I don't remember it well at all). I never really was a big fan of shooters. I never was interested in virtual killing. I didn't see the draw. Until I went to robotics camp over the summer. Almost every night, after learning about and building maze-navigating robots, we played Halo 1 on the computers in the lab, playing team slayer in blood gulch, boarding action and Hang 'em High until we got kicked out by the counselors (or tired, which is usually what happened). No, that's not me. That's Generic Google Images Man
Fast forward to December, and I get an Xbox 360 on Christmas. The first game I buy with my Christmas money is Halo 3: ODST, and I get sucked into the multiplayer almost immediately. I still haven't finished the ODST campaign. That's how addicted I've gotten to the multiplayer.
OK OK, you don't have to get all mad. HERE'S why Halo 3 is great. It's Great With Friends
The Sheer ridiculousness of Halo lends itself to being awesome with friends (or at least, nice random people in matchmaking). Having your friends along for the ride in the Warthog makes for an awesome time, especially if you have talkative and funny friends. "High Five" is likely going to become a catchphrase among me and my friend now. yes, that's really me and my friend in matchmaking. I'm on the receiving end of the high five, unfortunately. So Much Ridiculous Stuff Happens
The lofty physics in Halo 3 make for some pretty awesome stunts, and for some ridiculous occurences. flying mongooses, running over half of the other team in a warthog, accidentally getting stuck with your friend's grenade, sticking your enemy with a grenade across the map are all examples of the crazy shit that can happen over the course of the game. And it's awesome.
The Alien Weapons Make it Interesting
Sometimes bullets and grenades aren't satisfying enough. That's what the Covenant weapons are there for. The needler, the Plasma pistol, Plasma Rifle, and especially the plasma grenade, in all its sticky glory. There's more, but those were the ones I could think of off the top of my head. The Vehicles are Fun to Drive
They just are. their control scheme works very well (and it's basically universal for every vehicle), and they handle well (but not too well that it becomes too advantageous to use them). The warthog is difficult to drive, but rewarding at the same time. And of course, the turret seat is important in successful driving. Getting splatters can be hilarious and fun at the same time, and sometimes getting blown up in a vehicle can be just as fun as being the killer.
And that's about all I can think of. Remember that this is my opinion and in no way does this represent fact at all. Thanks for reading through my rambling, and I'm open to criticism. This was my first real blog (not counting my intro). Let me know what you liked (and especially what you didn't like). I'll work on improving it in the future.