Thanks for all the responses to this thread; I definitely agree on the merits of getting an MA first, especially one from the UK. I think it's a shame that a lot of American programs are getting rid of (or rather assimilating) seperate masters (how many still offer them: Columbia, Penn, IFA?) I think it offers an important bridge for students; a kind of rapid immersion into graduate study that can help with the transition from undergraduate level work. The UK masters degree almost resembles an accelerated version of the graduate experience in which you go from coursework to independent research and finally, one-on-one supervision with a dissertation advisor in the space of one year. My problem is that I wish I was doing it the other way round. While London is great (the Courtauld, UCL and SOAS make for a very dynamic art history 'scene') if you did your undergraduate degree there, as I did, it's perhaps not as exciting or fulfilling to go back to for an MA.
Having said that, it's a lot more affordable for British and European citizens (who get their tuition subsidized and are also elligible for quite generous government funding and grants for both masters and PhD). And of course MAs in the states are generally unfunded as well...difficult decisions! I agree with mims3382 about the timing issue too, as it seems like it wouldn't be feasible to start a one year program this year and subsequently apply for a PhD the following year. Lastly, how do people perceive American MA programs (Columbia, for instance)? Is there an attitude that if you're really serious about academia you'll go straight into a PhD, whereas 'terminal' MAs are exactly that: finishing degrees for those going into arts careers/curating etc.?