Looks like some folks are going to extremes here. If I choose to fish a 2wt, I don't need to have others tell me I need a damn 5wt instead. I fish for panfish, I like 2-3wt rods. They work well for me. I do not target carp with a 2wt, that's not what they were designed to do. For panfish and small to average size stocker trout, the 2 and 3wt rods are about ideal. For those who feel the need to walk the party line, and use a 9' 5wt rod that is as stiff as a frickin 2x4 for gills and average sized trout, then good for you. I for one like to feel the fish on the other end, not launch them into lower earth orbit when I set the hook.
If one is targeting large fish, then use the appropriate rod for the job. If you happen to hook into a monster while fishing with your ultra light fly rod, and your tippet snaps, oh well. It's not the end of the world.

Jeremy