[General Maximus]

the point thenry and craig are making is that the shub is a sub-standard router and doesnt actually support the features you are after, hence the suggestion to buy a proper router.

That being said, you should have plenty of juice to go around. The xbox isnt going to detrimentally impact anything for the pc and the only way the pc is going to kill things for the xbox is if you hammer your connection with torrents or newsgroups.