I still recall coming home around midnight with the Halo 2 in the steelbook case and being rocked by the epic guitar riffs of Vai and Satriani from 2. 2 even had some diversity with quieter, contemplative, and moodier tracks like Peril. I can't wait for Halo 2 Anniversary and especially waiting to see how they remix the soundtrack from that epic game.
On a side note, I'm surprised how much I like CE Anniversary's soundtrack. Some of those remixes are outstanding.
CE was outstanding, and then 2 built upon everything from CE and made it unbeatable. Heavy Price Paid was so epic to listen to in the menus. 3 I felt was just a re-release of 2 and Reach and 4 are just ok imo.