hey everybody,
i have lived through something similar...
after graduating from college in 1999, i entered a PhD program in biomedical engineering. this had been my dream for several years, and i fully intended to be a research engineer for the rest of my life.
about a year into the program, things changed, as they often do in life. i got less interested in doing research for the rest of my life and more interested in medicine. and i got married.
so, after two years of grad school, i finished up my master's degree and chose not to pursue the PhD. i was not surprised to hear that this is true of many many PhD students all over the country. graduate schools have a hard time keeping their applicants past the MS degree. (i think i heard once that only 50% who enter PhD programs actually get the PhD, but i can't back that up). a PhD is a HUGE time commitment, and if you are still in college, you have no idea how huge a commitment it really is. you will spend most of your 20's earning that degree. it is not something to be talked about lightly, and if you are saying "maybe i'll do this for a while, maybe i won't" then you won't finish it, period.
all that being said, i don't think it looks that bad to drop out of a PhD program. i did it, and i've gotten no hard questions at interviews about why i quit. i wrote a PS that clearly explained my motivation, and they have all accepted that. in fact, i think having my master's has only strengthened my application.
now, as to whether you should apply as a PhD with the intention of dropping out after the MS..... i don't know. it is true, PhD's are supported differently than MS students, and it is harder to be accepted as an MS student. but when as a PhD student, you will become part of team in a lab, people will invest a lot of time (and money) in you, and people will be counting on you. it seems sort of dishonest to me, but that's just my own personal opinion - you gotta do what you gotta do.
LL