Personally, I really don't like padded slings -- too bulky. I'm not big on ring slings either, but have only tried one (and it was padded, too) and the rings never held the fabric in place. I also don't care for having a lot of extra fabric - I prefer pouches regarding slings. I used a fleece Peanut Shell with Ellie. I'm planning to get a Solarveil sling this time around. It protects the baby from harmful UV rays, is lightweight but sturdy, and quick-drying -- all great features to me!
Here are some:
Khaki SolarVeil® Baby Sling :: Baby Carriers - Baby Slings :: Mamma's Milk
Kangaroo Korner - Adjustable Solarveil® Pouch
Wallababy :: Reversible Baby Slings NEW! Solarveil Reversible Pouch
Of course, everyone is different. My very favorite way to wear my baby(ies) is with a mei tai. I got a Babyhawk with Elle and have played around with the thought of maybe getting a Kozy as well (the Kozy has the option of a higher back and offers more support for a newborn without using extra blankets or "stuffins" of any kind).
P.S. - I did try one wrap with Ellie and didn't care for it much. Even when I figured it out and wrapped her snugly, the fabric was too stretchy and I felt like I needed to help hold her in with my hands. Again, I'm also not big on lots of fabric, especially in the hot summer.