Konni, we use the Kelty (m)

backpacks and they've been great. They have a frame such that the baby can sit in them while they're parked on the ground, and they're very comfortable. We have a "town" version (for J) and the "country" (for chunky S). Both are fine.

We got ours at www.snowleopard.com, which at the time had them on sale. Mysimon.com can probably steer you to the best prices on any model

Karen