Agree with my main man Wagner...
As long as your USMLE score isn't horrible, it will put you on a level playing field with the rest of the applicants. I didn't take the USMLE, but scored very well on the COMLEX. I definately had more than enough interivews, but some places that I was strongly considering (MCV in VA, for example) didnt' give me an interview... I feel that it is because I didnt' take the USMLE (a fellow DO student who scores like I did on the COMLEX, but did have the USMLE got an interview from there).
So, my point is you will still get interviews without the USMLE, but might get a few more if you do submit the USMLE.
Q, DO