I like this one as a do it all, mostly. I purchased another one last week. It has a fat round profile which would be great for rappelling down in an emergency using a Munter hitch if you know how.
With a keylock nose and a compact size, the pear-shaped Metolius Element Locking Carabiner is ideal as your everyday belay carabiner for rock climbing.
www.rei.com
I have 2 connected to my bridge here.