In terms of job placement, no, the rankings really don't matter. In some PT practices, a warm body with a license may suffice.
However, I think that you also really need to consider how you feel about the education you receive. I interviewed at schools that ranked in the top ten to schools that had not participated in the process (those schools you see in US News with the N/A next to them). Presently, the ranking process is rather ridiculous, because it is the chair of each department which evaluates other schools. Those that do not participate receive the N/A.
All that aside, I have to say, I was quite unimpressed with the low to unranked schools. These tended to lack cadaver labs in which PT students did dissection (which I feel I have learned a TON from), faculty/students whom seemed less dedicated or at least had less understanding of our importance as practioners of choice in regards to prevention and muscular dysfunction, fewer clinical hours, lack of research opportunities, fewer professors who were Ph.D/ board certified, and/or lack of interaction in onsite hospital and rehabilitation settings.
In the end, I chose the best program that fit my desire to the best clinician I can be in a few short years, and it included all the aforementioned criteria. (It also happened to be in the top rankings and is EXPENSIVE!) I TOTALLY realize that cost is a huge factor, and know that I will be paying off these loans for a very long time. It is possible to obtain scholarships, and loan forgiveness programs are a possibility after you graduate if you are interested in going that route.
I'm not trying to encourage you to spend lots of money, but make a list of the components of a program that you feel will make you the best PT.
We have a huge duty to the public and future patients to be as knowledgeable and educated as we can- we should not try to skate by w/ the bare minimum. Presently, our profession and the health care system at large is undergoing big changes, and I really feel it is imperative that we are equipped with skills that enable us to sucessfully work with our patients to produce good outcomes.
These skills do include the eval, recognizing appropriate treatments vs. risks, but also include your ability to interact w/ patients well, and participate w/ them in the treatment process.
I know this is way more than you probably wanted, but the long and short of it is... no, the rankings don't matter in future empolyment if you just want to work at some PT mill where you just eval 10- 15 patients a day and then turn them over to a PTA.
Apply to a wide range of schools, get a good feel for their programs, and ask the current students and professors some tough questions about their programs. Sorry for the long rant, but it is important for you to get a great education. PM me if you like- be happy to rant more!
