I've made it clear he's not my first choice for president. He's not even my first choice in his party. If I were given only a choice between him and Hillary Clinton, I would take Clinton even though I think she got where she is more from riding on her husband's coattails than her own merits (give me a fucking break if you think she sat on the board of Walmart or was made partner at Rose Law Firm without ANY regard for the fact she was married to the governor of Arkansas). She may have risen to great prominence on her own. But she didn't. Not only that, she stuck with him and parroted his lies blaming his political opponents instead of him when he got caught fiddling around with interns and lounge singers. If she wants to have an open marriage, that's her business. But attacking "vast right wing conspiracies" for your husband's sexual appetite turns personal lifestyle concerns into politics. I still resent that, and I'm not even right wing.
Why Hillary over Obama? Because I think she's the more pragmatic of the two. She had her ass handed back to her in grand fashion when she tried to take over a seventh of the national economy as an unelected official. She also found through the rest of her husband's administration that she can get more of what she wants through piecemeal changes than radical changes.
In contrast, I'm wary of anyone who offers "change" for the sake of change. As good a speaker as Senator Obama is, I don't care for change for the sake of change. I don't care how well someone delivers a speech (I'm more likely to read it than watch or listen anyway; Obama is much less electrifying in print). I disapprove of the policies where I know Obama's positions and what "change" will mean in those areas. I don't think he's mainstream -- except to the far left of the Democrat party (who tend to confuse themselves as the mainstream because they isolate themselves from the real world and really don't know any better).

I think Senator Obama will lose a lot of his shine as soon as the nomination is secured. That's when the spotlight turns away from appealing to the party ideologues and moving back to the center to appeal to moderates and independents. That's when he'll have to explain the kinds of changes -- in detail -- he wants. I don't think he can win over the middle who decide elections.
I won't be too worried even if he is elected. We won't abandon Iraq in the irresponsible manner he says we would in his administration. He won't have super-majorities in Congress to rubberstamp so he'll have to compromise if he wants to get any of his more grandiose schemes passed.
That will alienate his more hardcore "pro-change" supporters. The irony is our system was set up to prevent change and radical shifts -- to protect the country from the people jumping on the Obama bandwagon.