Not familiar with O'brien, but he sounds like he's in the Prechter camp. Yes, deflation is what we're experiencing now and Bob Prechter has been predicting another stock market crash since last November--he said gold and silver would be crashing back down, too. Six months later and the market is holding up (somehow) and gold has not crashed. Silver has gone nowhere.
The reason I and others here are sticking it out is because we still believe inflation will be the end result. Deflation can't be tolerated, but rates are already near zero. That means Bernanke WANTS inflation. The debt is already unmanageable and deflation will worsen it. Bernanke will print more to stop it. They will print their way out. The Fed/Keynesians greatly prefer inflation to deflation. Flooding the markets with liquidity is how they handle 'bad times.'
Short term...anything can happen, but a hyper-inflationary depression is on the horizon.