Dear B.,
I know I'm responding so late - you're probably all set with your new baby carrier by now. : )
I've worn a lot of different things - Snuggli, Baby Bjorn, Ring Slings (padded and unpadded), ERGO carrier. My favorite is a padded ring sling, specifically SlingEZee, which comes in 5 sizes. Next in line would be the ERGO carrier, which is similar to the Baby Bjorn, except it is good for their spine (they're not hanging by their crotch).
Most people who buy a sling get a Nojo from Babies R Us. The Nojo claims to be one-size-fits-all, which is impossible for a padded sling. So they have trouble with back pain unnecessarily. Also, I hardly EVER see anyone wear a sling correctly - which, again, results in back pain. I've tried very hard to put a lot of good content on sling wearing on our website, if you'd like to check out those articles. Check the "related articles" area for more than this one...
http://www.nurturedfamily.com/baby-sling-problems.aspx
The best to you,
R.