In the first 2 months of life I really recommend an unstructured carrier (doubly for Mom). You can see our review of the Moby and Infantino Mai Tai.
Once your baby is big enough though, you may want to get a structured carrier for your and their comfort. When our first was born there was only one company that made "ergonomic" carriers, i.e. ones that were comfortable for the parents. They called themselves "ergo" (get it?). We got one and it was great. It was an easy way to transport the baby, say onto an Amtrak train, and still have hands free for all your stuff. It also had a "sun hood", which was great not just to protect the baby from the sun but also to help her sleep when we needed her to nap on the go. It also had a pocket in the front which was a convenient place to store your cell phone/keys etc. if you were just taking a walk around the neighborhood and didn't need that much stuff with you. Our baby also just enjoyed hanging out in it while we did other stuff and often it was a way to get her to nap when she just plain didn't want to. We used it with some frequency until the kid was about a year old. In fact we have so many pictures of us carrying her around in it (in the carrier at a wedding! at a train station! with dad working at a computer!), it was hard to just pick 2.
Overall, it was great but from my perspective it had 2 downsides:
1. There was no front facing option with the "original" carrier, which was the only one available at the time. Facing forward would have been much more fun for the kid once she got to be about 4 months old. Both Ergo and other brands have since come out with structured carriers that have this feature.
2. When the baby is under 3 months, you have to use this really bulky and hot insert with them. This one was the real bummer, especially since our first baby was born in June and our second in July. Even in the most recent version of this ("the 360") they haven't fixed it. Given that other options are available, if you think you'll want to use the carrier before the kid is 3 months, I would say it's definitely worth considering a different brand.
