To me, Thanksgiving is about two things- good people and good food. Everyone works their butts off making delicious food of some sort ("you bring the rolls, I've got the pie" kind of thing), you sit down with whomever you consider family, biological or otherwise, and you spend the day appreciating the people you are lucky to have in your life. I'm big on the holiday- and a pretty firm believer that no one should be alone on Thanksgiving. Depending on the crowd, there are other traditions, a main one being football (a pickup game in the backyard or watching the game on tv), and you could have a dry Thanksgiving or bust out the wine and merry things up a bit. It seems to me that with all the craziness that tends to happen towards the end of the year (ie, for us students, the finals and other stressful things coming up soon) it's important to take some time to step back, have forced relaxation, and spend a little time being grateful and celebrating what you have, no matter how little or much.
Plus, who doesn't love turkey and mashed potatoes? And pumpkin pie... mmm... pie...