If you think the S&P will run to 1K, you should be holding some ETFs probably. But my lingering skepticism has turned to full-on bearishness and I think people are best holding only those things they're holding long-term, plus cash and possibly even short ETFs.
Still though. These days are pivotal. Gotta be flexible and ready to flip if you're wrong. If you're in cash, you can wait until the direction is clear and hop in then.