So many other people have commented on the fact that the inauguration and MLK's birthday coincide that I'm not sure what I can add, except maybe something in the realm of personal experience.
I was in, I think, third grade when I first learned about Dr. King. The first image I remember seeing of him was, I think, this one — a picture of him being booked by the cops in Montgomery. The contrast was shocking: here was this man who stuck his neck way the heck out for his countrymen, being arrested. Good guys don't get busted was, I think, the unspoken assumption being questioned by all that.
That made his line about "to work together, to pray together, to struggle together, to go to jail together" all the more poignant when I heard it. Not that one has to get thrown in jail to prove the courage of one's convictions, but that one should accept it as gracefully as possible if it is necessary — and that one should always take every other legitimate step first.
I feared for a long time that there was a general sense in this country that legitimate political action — writing letters, knocking on doors, making voices heard — was losing favor against "direct action" — everything from sit-ins to violence and sabotage. With the latter, you at least got the frisson of feeling like you got something done, even if all you did was alienate people who might once have been sympathetic to your cause. I hope that feeling has started to change, that intelligent political participation is possible once again.
It's hard not to be excited today, not just because a black man is taking office — but because a man with more than a little brains and insight is stepping up to the podium. And, in the end, that's all that should matter.