I started a thread not long ago that seemed to look into this issue (titled "I have a masters, do I want a PhD?")
I've also done some more research on my own & had candid discussions with some of my ex-professors and friends already working in a clinical setting.
This is what I basically got out of it (others are free to debate):
1) A clinical PhD makes the most sense (in terms of time and $$$) if you plan on working in an academic setting (i.e. tenure position), doing research, or working with schizophrenic (or comparably challenging) populations (likely in a hospital setting).
2) If you plan on doing mostly clinical work, a Masters degree might make more sense. For example, although you may learn more 'clinical skills' in a PhD program, you'll also have to do research & publications and devote a lot of time and effort to learning things you will not likely use in a clinical job setting. This same time (often 4-5 yrs post-Masters degree) can be spent getting supervised clinical experience in the field, taking additional courses specific to your area of clinical interest, attending new therapy workshops etc.
In sum, a person with a PhD degree will not necessarily be a better therapist than someone with a Masters degree that has put in some additional work.
3) Although it varies by jurisdiction, in most Canadian provinces you can be called a psychologist (sometimes a psychological associate or therapist) provided you jump through the same clinical hoops first (i.e. supervision hrs, EPPP, etc.). I'm still waiting to hear, but from my understanding, you would need extended (if not indefinite) supervision while in practice. I'm sure it's something similar in the U.S.
I too am interested in doing primarily clinical work.
It seems to me that these programs need some serious revamping in order to tailor to those who do not intend to go into an academic or research direction. I think PsyD programs are maybe a step closer to a purely clinical degree, but in Canada at least, they are too few and too expensive. I wish there were a way (post Clinical Masters degree) to do whatever extra clinical work is deemed necessary to be given the title of 'psychologist' without qualification. I really don't feel like spending another 4-5 years having to conduct studies & publish papers in order to be called one.
Anyway, those are my thoughts
Hope this helps or at least stirrs up some discussion