Well, my youngest child is almost one year old, and I am going to have to make myself give up my baby carrier collection pretty soon. My oldest child is almost seven, and he was the reason for me to immerse myself in baby carriers following his birth - he needed to be carried almost all of the time. Unfortunately, the one carrier that I had planned to use most - the Baby Bjorn - was the one carrier that he resisted the most intensely.
I had purchased a sling (Maya Wrap sling) in advance of my oldest son's birth, and when it became apparent that he needed constant carrying (and not in the Baby Bjorn!) I started to use that. It took him a little while to get used to the sling, but once he did it worked great. He was a big baby (20 pounds by 4 1/2 months) and tended to scream hysterically when he wasn't carried (including when I tried to place him in the stroller), so the sling was truly a life (and back) saver.
As my son became heavier and older, I looked into the various other types of baby carriers available. I purchased wraps, pouches, soft structured carriers (in particular, a Kozy mei tei and an Ergo) and learned more about baby carriers than I ever knew existed! There is a wonderful website at http://www.thebabywearer.com/ for those who want more information. In the end, I always returned to my sling and pouch (primarily the pouch as he got older) since they were the easiest to get him into and out of, though some of the other carriers were more comfortable (especially the wraps, but I just couldn't deal with all of the fabric!).
When my now-three year old was born I purchased another soft structured carrier - a calyx by Mama by Designs (http://www.mamabydesign.com/) and found it the most comfortable carrier I have ever owned for doing extended carries. Unfortunately, though easier to use than many similar carriers, it is still more awkward than pouches, especially for very short carries or with a fussy baby (who likes to be in front). So.... in the end I remain mainly a sling/pouch proponent (for newborn / older babies, respectively) but with a very favourable review of the Calyx as well! I guess I will keep some pouches and the Calyx for now, but it is time to start making some room in the garage and divesting myself of some of the other baby gear!