Well i am up too the last level but dont want to complete the game, i dont want Halo to end!!

Well anyways, i haven't got Xbox live but im thinking about it, is there anything really important i need to know before getting it.
[img]http://i188.photobucket.com/albums/z215/Gezza01/fableandhalogezzado.jpg[/img]
[color=red]That that dont kill me can only make me stronger.[/color]