I think you also hit another key point there. Any image can look great on the web, as they are typically scaled down. I'd dare say that if all of your images were for web use only, then the KM 5d would be more than enough, and the A100 and A200 is getting to be far more than enough. However, for printing and high-end use, then the A100 and A200 is the bare minimum these days. Also, for web use, I think the 18-70mm kit lens is sufficient, but struggles every where else. [edit, forgot to add] Otherwise, I completely agree, good lenses means good pictures for good printing.
For me, the A850 is definitely a good choice, I don't need the high speed frame rate, as I don't do sports shots, having a 98% view finder is still a step up. However, I think I'll get which ever, on the second hand market falls into my price range first.