Based on the title of the thread, lets think about this real quick.
1. Spend 300-600 on an Xbox One FOR HALO ONLY
2. Spend however much it would cost you for a Rig and play the millions of games available on PC (OFC you would have to buy the majority of the games but same with the Xbox)
While I completely respect your choice to get an Xbox over a PC if you do, I personally would choose the PC anyday.
(PLEASE NOTE THAT I AM NOT AN XBOX HATER! I KINDA WISH I HAD AN XBOX ONE FOR THE NEW HALOS COMING OUT BUT IM NOT GOING TO BUY ONE SOON AT ALL AND WOULD RATHER GET A NEW GPU OR SOMETHING!)