Nice, I re-played the Bungie trilogy over the holidays. Great, great memories, although I only realized how to turn off the Remastered graphics on Halo 1 after I finished the campaign solo. Am doing the un-remastered campaign co-op with a friend. I actually think the visuals stand up surprisingly well and the un-remastered music is greatly superior in my opinion. There is just more atmosphere to the Bungie version. The Remaster is too bright and overdesigned, especially 343 Guilty Spark.
Am going back and forth between 4 and Reach right now. I like the Chief-Cortana stuff in 4, but otherwise I think it is a lot weaker. The plot doesn't make any sense unless you seek out the Terminals, which is poor storytelling.