Today was really disappointing if you're an Obama supporter. He may be able to pick up some momentum coming out of South Carolina if he wins convincingly, but the longer this race wears on, the better Clinton's chances, simply because her name is more visible and she's the establishment candidate. It seems to me what Obama needs is a second media honeymoon after a big win in South Carolina, reprising the "movement" storyline going into super Tuesday. Otherwise, aren't Clinton's national numbers going to be overwhelming? I suppose she could always self-destruct, but that doesn't seem likely.
By the way I'm definitely an Obama supporter. I like his politics, I like his style, and I like the idea of what Kerry (shudder) called transformational change. He's got by far the biggest upside potential of any candidate in either party, and he's got a mind and a face that will go a long way toward reviving both America's self image and her image abroad. Plus I'm just not excited about Hillary Clinton. The attacks we've seen from her since Iowa -- particularly on race and the notion of change -- make her seem insubstantial and hellbent. I don't like that she's campaigned (even a little) on the fear of a terrorist attack. It scares me a lot that so far these tactics have won the day with Democrats, at just this moment in history.
I'm also disappointed that McCain won in South Carolina today. I think he's the most dangerous candidate in the Republican field from the standpoint of electability, and in particular I think his sort of maverick persona matches up well against Clinton, whose biggest weakness might be the perception that she's scripted and insincere. Sure, a Clinton vs. McCain race would have other interesting dynamics -- McCain doesn't seen to do well as a frontrunner, and Clinton's ability to bring in Republican women voters hasn't been tested yet -- but this contest is the only plausible matchup that Republicans could really be feeling good about.