Nash, I think that for many people it's not so much a choice, as it is a total lack of one. Some people would rather take a poison pill than vote democrat. To them, that vote signifies the end of the free market, the onset of socialism, the end of good old American values, etc.... There may be credibility to this, there may not. To those people, that poison pill was GW. To these same people, the fact that he went into Iraq to impose American values created appeal in 2004 where there was little or none in 2000.
Your question therefore has a built in answer. Why did people vote for GW? Because he ran. They would have voted for anyone running in that slot. Anything but a liberal.
GW's bible thumping and sanctimonious nation-building, however, has changed a lot of people--opened their eyes to the ugliness of brainless self-indulgence, hubris and maniacal ego-centrism. I am one of those people.