Yep, Ergo is a good choice for a structured (with buckles) carrier. There is also the Toddler Patapum or the Sutemi. All three can be seen at attachedtobaby.com
Personally I prefer a less structured carrier like a babyhawk. They are easier to share w/DH and so cute! You can wear it on your back, front, or hip without an issue. Check em out babyhawk.com!
As far as wearing your newborn...all the structured carriers I think reccomend something like 6mos (unless you buy the ergo infant insert). You COULD use them with a newborn but IMO a mei tai is a little more snuggly.