I just picked it up and played again with a friend. It's stood the test of time pretty damn well. I may even like it more than Halo 2 (and definitely more than 3), but I sure miss the dual-wielding. I was inspired to re-post a review I wrote of it before Halo 2 came out.
I remember the first time I played Halo I was completely blown away. It was so huge compared to other games "back then."