Two words on holds. One is that Ezra Klein has a good, clear explanation of how holds work.
Another is that one thing you hear about the Senate’s countermajoritarian devices is that these are a good way of letting the political system take account of preference-intensity. If that’s the idea, though, we should modify the rules so as to make it a bit more arduous. Like maybe to hold up a nomination a Senator needs to do a headstand (with an assist from staffers if necessary in athletic terms) on the Senate floor and say “I Richard Shelby wish to delay a vote on [Person's name] until tomorrow, February 6, 2010.” Then if you want another day’s worth of delay, you need to stay in town and do another headstand. That way if you really and truly cared, you could show the world.