Yeah, I was talking to you. Before getting a 360 (which took a lot of persuasion) I was pretty much in the same camp as you, it was really using the controler (playing Lost Planet) which sold me. As you say, compared to the controlers i'm used to (sorry, but the Duelshock is horrible) it is very usable. The convenience really can't be understated though, given the intigrated friendslist, voice communication and matchmaking, it's hard to go back to online PC gaming just because of the pre-setup and coordination required. Again, this really isn't somthing I appresiated before I got a 360, even if it makes me 'lazy'.
Guesting is where you can put more than one player from a console into an online game. EG, in Halo, you can actually have 4 players in an online game playing off the same console. It would be an instant seller for the 360 version of Dead Rising for myself and Llyranor because we have people constantly around who'd want to join in. If you don't have any friends it's irrelivent though.