Bullitt: one NetNewsWire style to rule them all
The main selling points of Bullitt all have to do with readability. Column widths are optimised for your viewing pleasure, and images up to 700px should fit comfortably into the layout. Titles are handled with a neat, elegant slab-serif, and each site's favicon is displayed in the heading. The overall look is extremely easy on the eyes; this is definitely my favorite style for reading long articles. Even more attractive, Bullitt uses css ad-blocking (as if it weren't clean enough already!)
I still endorse the 10 styles I covered before, and this sort of thing is definitely a matter of taste. If none of those really struck your fancy, though, give Bullitt a try. After using it for a few weeks, I can't imagine going back to anything else.