I guess my reasoning for 2x10 would be that I don't use my big ring, but I would like a little more range out back. If I really had my way, I'd love that 1x11 that's coming out, but I think that may be out of my budget range. I also like the idea of simplifying my shifting.
As a side note, I bent my rear derailleur hanger, and I'm pretty sure I bent the cage on the derailleur itself too, which prompted my thinking about drivetrain upgrades.