I LOVE my Beco Butterfly! I tried out the Ergo, the Baby Hawk Oh Snap! and a Mei Tai, all of which are also toddler-carriers, and the Beco was by far my favorite carrier. Each one fits slightly differently (especially depending on your body type) and has different great features, which makes it difficult for me to say which one you will prefer.
I highly recommend http://www.thebabywearer.org and http://www.frogmama.com/ Both are sites about baby-wearing, and both have great comparisons of different carriers. TheBabyWearer is a forum where mothers discuss different carriers, ask advice about them (much like this site) etc. You do have to sign up with an email address, but they don't spam you or sell your information. FrogMama is a mom in California who sells these products (at the same rate you can find them elsewhere, no added costs), but she's very helpful (she even has videos comparing different carriers) and (this was my favorite part) she has a fantastic return policy, so if you want to try a couple carriers out and then return those that don't work for you, you can! This makes it a lot easier for those of us who don't live near shops that sell these carriers. Please check out the sites to make sure that you get the carrier that is best for you.