I swear I bought every carrier recommended here (lots of money wasted, but I do like bits of all of them!)
I use the Hotsling...it was great with DS was tiny in the cradle hold, then there was an akward phase when he didn't care to be in the front carry. Now that he is big enough to be in the hip carry, it is great! It is so easy to fold and put in your diaper bag. Plus, it has cute, fashionable colors. They just came out with some cool funky patterns, too! You should find a boutique in your area that carries it and get the correct fit. I know our local baby boutique will fit you (even if pregnant) and let you exchange it if it is the incorrect size. The size makes all the difference.
The rest aren't slings, but front or hip/back carriers too.
Also have a Bjorn Active. We used it until DS was about 4 months, but after all the hubbub I have read, it has taken a backseat. It has been by far the best to use for walks when he had no head control though. It got us through some crying spells like a charm, too.
Babyhawk Mai Tai is next. I love it now, although since he seemed to be in pain in it until about 5 months in it (his little legs and my big belly don't get along well and they are supposed to wrap around your belly), it didn't get any use until recently. It takes a bit to tie snugly, but the colors are fun! Definitely not for newborns, IMO.
Belle Carrier. Yuck. Waste of $$. Get the Ergo. Just traded in my Belle for the Ergo and I LOVE IT!!!! If we are lucky enough for #2, I will get the newborn insert. With out it, they recommend 4 month + only (same carry concept as Babyhawk. Little baby legs around your belly. With the infant insert, it looks like they ride "side saddle.")
We use a Chicco travel system and love it, but if you are steering from that, I can't help. But, keep in mind, Chicco was rated a
best buy by CR. They have the Keyfit 30 now which is a rear facing bucket seat that holds babies until 30 lbs. We also just bought a Britax Roundabout and will probably get a Recaro Young as well for when DS graduates out of his bucket.