Like Joe Klein, I think John Harris and Jim VandeHei have compiled a solid brief against nominating Obama. But, like Klein, I also think they way, way underestimate the extent to which Hillary's been "vetted." We've barely stepped down Bill's trail of post-presidential dealings--the tax-return dump only gives the vaguest hint about where that $109 million came from. I'd expect much, much more in the Colombia-Kazakhstan vein were Hillary to win the nomination. Obama has chosen not to press this stuff, but the RNC and various GOP 527 groups certainly would.
Just take a look at this list if you don't think there's ample fodder for them.
Also, I think a lot of commenters have misunderstood where I'm coming from on this stuff. I'm not arguing that Obama doesn't have big general election liabilities. He clearly does. I'm just arguing that he's almost certainly going to be the nominee, that that's not going to change even if Hillary spends the next several weeks unloading on him, that the only thing this course is going to affect are his chances in the general election, and that, even if Hillary did some how pummel him hard enough to wrest away the nomination, it would be close to worthless since she'd have generated so much ill-will toward her among Democrats.