So it came down to two issues for me -- the level of detail and thoroughness of various plans (esp. universal health care) and the candidates' stand on (the Iraq) war.
Clinton clearly has the better resume on the first count -- meticulous and well-crafted plans all around, reflecting her experience and how deeply she cares about issues. For example, see this Krugman article (timed slightly poorly, coming as it did the day before Super Tuesday, compared to the Kennedy family endorsement, which gave voters some time to let it sink in) for a nice analysis on how the Clinton health care plan would cover nearly twice as many people as the Obama plan would.
On the Iraq war front, Obama had the clarity of thought to step up in October 2002 (on Gandhi's birthday, in fact) and call it a dumb and rash war, adding:
I know that even a successful war against Iraq will require a U.S. occupation of undetermined length, at undetermined cost, with undetermined consequences.
I know that an invasion of Iraq without a clear rationale and without strong international support will only fan the flames of the Middle East, and encourage the worst, rather than best, impulses of the Arab world, and strengthen the recruitment arm of al-Qaeda.
In a matter with complex details, Obama (and his team) didn't possibly have the best analyses of their health care package, but that's something that is fixed at a smaller cost: the studies of the kind Krugman points out might lead to Obama's plan being revised, Obama might simply incorporate several elements of Clinton's health care proposal, etc. However, in a matter of international significance, in a matter that involved serious cost (and not just in dollars) to the country, Hillary Clinton failed, where the junior senator from Illinois displayed tremendous foresight and levelheadedness.
For this reason, I voted for Obama.
The vote is also strategic, to some extent: my thinking is that McCain (or any of the other Republican candidates) might find Hillary an easier opponent to defeat simply because I think that America is less racist than it is sexist. And that is an outcome that I wish to avoid entirely.