We've written before about our love for Kelty infant/toddler carriers. We like them so much we own 3 different styles (1 front carrier and 2 framed backpacks) even though we only have one child.
Asha at Parent Hacks tipped us off to Amazon's Annual KeltyKIDS sale where the carriers and accessories can be obtained for 20% or more off. If you were already looking for a new one, this might be a good opportunity. We bought 2 out of 3 of our Keltys second-hand. They're very well made and durable so you can also find nice ones at consignment shops and yard sales.