I don't disagree with Wladimir. Anyone who has been on this forum long enough may know I was among the first to propose off-chain transactions as a critical part of scaling Bitcoin. My views there haven't changed. I still believe they will be key.

However, it's also worth noting purely off-chain solutions are likely to look more like present day centralized payment systems than decentralized P2P currency. I believe what we'll ultimately see is a combination of many technological options mobilized to keep Bitcoin working smoothly (Gavin also talks along these lines, see signature link).

I believe it's smartest, though, to build Bitcoin with the most utility possible, as a sort of if all else fails option.

People don't build cars with only one seat and tanks which hold just 2 gallons because people mostly make short trips to grocery stores and often travel alone. Buses and airplanes exist complementing cars, transporting large numbers of people, including cross country. However, the full utility of a car means if no other option exists a standard car can still get that job done. That's how I view Bitcoin. Nobody knows exactly how the future will look, but it won't be black versus white. If more alternatives ease the transaction load on Bitcoin then everybody still wins.

Gavin's latest size limiting plan doesn't alone account for handling all of the world's transactions; not by quite a long shot.