What are some of the best sites to play chess? What are some of the best sites for online chess?

Free sites with friendly communities are better.
Chess.com has become a hot spot, with live and correspondence chess, along with tactical problems, articles, etc.  The live chess is OK, but not the best. 

ICC or playchess are the best for live chess, FICS if you want free, but it doesn't have as many titled players or features.  Those sites will also have video's, live commentary of top level tournaments, and much more.