If you are talking about the "hiking" type baby carriers, I would say OK, but you'd still need a stroller. The baby probably want to nap at times and then your farced to go back to the room rather than let the little one sleep in the stroller. For the same price as one of these backpack things you can purchase a lightweight stroller with a canopy, that folds easily and reclines. I do not suggest bringing a large stroller that is part of a travel system! There are also places where you can't bring strollers, restraurants, attractions, etc. the backpack can come in handy while waitng in line. When DS was 9months we brought the backpack and the LARGE stroller. We survived, and DS enjoyed being up high and looking around some of the times, but also needed to nap in the stroller.
Others on this site have taked about slings and other carriers. I've never used them, but I think the bottom line is you'd still need a stroller unless you plan on spending all nap/sleep times back in the room. Besides, a one year old can get VERY heavy after a while if you have to carry them all day!