I wore all of my babies in a sling, often for their naps. If I wanted to sit down and read or rest, it didn't disturb the baby. Hearing my heartbeat as they slept kept them very peaceful. Besides being able to wear them against my body while I work, it helped me when I did choose to lay them down on the bed after they fell asleep. I simply leaned over until the sling (with baby in it) rested on the bed, then I eased my head out through the loop and opened the sling. Baby never stirred. Babies worn in slings cry less, since they are right there against you, and they learn more/more quickly. As they are being carried around they see more things, absorb this stimulation. It promotes attachment, which is wonderful. You just feel more connected with your baby. Dr. Sears has a good summary of the benefits: http://www.askdrsears.com/html/5/T051100.asp#T051103.
I wore mine in slings until they were about 3 years old and it is one of my favorite memories. If you're carrying a kid anyway, might as well have a sling help distribute the weight. I like the Maya Wrap since the tail is not sewn shut and I can flip it up to cover baby's head if needed. I also like the Baby Bundler, especially for newborns and you can do a back carry for both of these (like piggy back) when the child is older. Both also work with the hip carry for the older baby/toddler.