Eh... If you play only one or two games, that would save money. Also, as much as I love Halo 3, I've barely touched it since I got COD4. It's hard to get used to Halo's slow pace after COD.
You may be different than I am in this regard, but some of the most fun times I had in an online game were on Halo 2, and I was atrocious at that game. I rarely won, but I loved it.
Oh, and it's good to see you back.