Lancelot asked me to elaborate, so I will do so briefly and without much copy-checking.
All attempts to render my current perception of the divide between the modern GOP as led by Bush* and the modern Democrats as exemplified by Dean will, of course, grossly simplify. Those politicians with whom I've agreed most strongly have always been socially liberal Republicans, but they seem badly marginalized. Meanwhile, Clinton-era Democratic pragmatism meant that I felt some genuine enthusiasm about the direction of government. For a while, the Democrats moved away somewhat from statism in economics while largely maintaining their socially liberal roots. Generally speaking I rank social freedoms well above economic ones, so if the economic freedoms are at all comparable, I almost don't care at all for comparison's sake.
Then came Bush, who seemed at least as determined to spend as his Clintonesque opposition, but was socially very conservative - more so than Dole had been. It seemed a step back in every direction. I have complained about him in length before, so details are pointless, but I became so alienated from the Republican party that I would have felt safe voting a straight Democratic ticket anywhere outside New England.
Kerry was, of course, a disappointment, largely for the same reason Dole was in '96: he seemed to abandon his best parts in order to grab his running-mate's consituency. Dole took on Kemp's stupid tax-cut plan** while Kerry took an appalling position regarding outsourcing similar to Edwards' -- where it wasn't incoherent.
If Kerry sacrificed his best economic policies, Dean never had any. Worse, his form of social liberalism is combative, anti-intellectual and insulting in all the same ways I find the far right. I might agree with his positions, but he puts such an ugly face on them that I'd rather they not be advocated at all than be stigmatized with such unsympathetic and fascist rhetorical style. Hillary Clinton, his only current rival for influence, is... ick.
For Derek Obama I hold some hope, but he's so inexperienced, his promise for national politics is still well in the future.
I'll still vote Democratic against current GOP leadership because I think they are terrifying and I'll do just about anything to maintain reproductive freedom and/or advance gay rights, but if a moderate Republican could make it past the primaries to face a Dem like Dean or post-Edwards Kerry, I'd vote for him in an instant. That I'm even dreaming of that possibility, however, is largely a sign of my increasing horror at what's become of the Dems rather than any real belief in the possibility.
* My saying this will sound odd, but compared to House Republicans and the likes of Santorum, I feel almost warm toward Bush and his administration.
** Cutting taxes qua lowering the overall tax rate does nothing to shift capital to the private sector -- only reducing government expenditures does that. Otherwise the government must borrow the exact value of the tax cut back from the economy. Real interest rates in '96 were decidedly positive, so incurring debt was definitely *not* lucrative. Since it's been negative through much of Bush's administration, it's been largely a wash, so my complaints center more on the how of the tax cut than the existence at all. I still expect real interest rates to return to large positive values, of course, and *then* I'll be more upset about the grown debt, but that's the future.