Here are five reasons I don't believe this rally has legs ... and why I find XLF's 10% run today rather incredible.

Well, Matt—if your research holds any water, today must have been a BOOM day for the (RAFI) fundamentalists out there. And this huge rally for XLF? I don't believe it for a second. In fact, the same dangerous impulses that led me to buy XLF at $15.07 (and see it promptly drop to below $6) are urging me to sell now that we're almost touching $12. After all, in that October binge of ETF buying (heavy on XLF and FXI—that would be the SPDRs Financials and the FTSE/Xinhua iShares for the less-ETF-focused among you), I'm actually AHEAD right now ... after a disastrous start.

In this environment, I'm looking forward to talking to Rob Arnott this Thursday at 1:00 p.m., where he'll be doing a webinar

While Jim Cramer and others are wringing their hands, the people I respect most are turning bullish.

At least, over the long term.

Let's start with John Bogle. (Doesn't it always start with John Bogle?)

Judging by the series of interviews he's been giving lately, Bogle is very worried about the U.S. economy. As he said in an interview with Forbes today (highlighted by Murray Coleman in our invaluable new daily news roundup), "it will be a year-and-a-half to two years before [the U.S. economy] turns upward."

That doesn't mean investors should be sitting on the sidelines. Far from it. Bogle says the market may be undervalued by about $7.5 trillion right now, and thinks that the market has likely over-discounted the impending recession.

Bogle's not alone. In the forthcoming January/February issue of the Journal of Indexes, Rick Ferri (a great financial advisor) calls this "the greatest opportunity in our lifetime" for