Halo 3 hands down. I was never a huge fan of any of the other Halo games..

Halo 3 Best for multiplayer and the memory of grinding for that recon. i remember beack then in 09 or 08 when people saw bungee employees with the flaming helmets and recon people would shit bricks. those were the days when halo was in its prime. I thought the campaign was the most memorable and fun. Also the Community in the prime of halo 3 was the best. I just wish Halo was still like that how it was back then
I just dont understand why not as many people play it and instead play cod.
HALO 3 Best ever
If any of you guys want to play some halo on 360 msg @Nertiaa

Halo 2 by a mile although Halo 3 was really good as well. Halo 4 and Reach were the worst multiplayer wise.

Halo 2 was the best multiplayer halo for me. That's where it all started with Halo MLG.

I have invested so many hours into Halo 3 and I still don't get tired of it! Definitely my favorite game of all time!

Definitely Halo 3. Spend so much time with this game

Halo 3 for campaign but halo reach and halo wars for the multiplayer but the campaign on reach really irritated me due to straying away for the master chief campaign and halo 4 killed the series!