Just wanted to second this : ) So far I've been very successful with my application process and have also gotten into several programs, including one "top 5" (not that that really means too much, I think it's all about fit since any program will get you a job. I just wanted to show I'm being taken seriously as an applicant at all different types of schools with my USU prereqs).
My main point is, I think if you are a strong applicant (I mean solid GPA, good letters of rec, above average GRE scores) ANY graduate program will take you very seriously as a candidate regardless of whether or not you took your prereqs online or in class.
I also want to add that from person experience, the graduate programs I've applied to seem to really value seeing tough classes on a transcript (hard science and college level math courses). I have what in SLP would be considered quite a low GPA but took a lot of math and science courses, and they seems to have actually helped me in spite lowering my GPA somewhat. I feel like that's sometimes overlooked by applicants because so many people seem to be talking about their GPA and the average GPA of programs. However, I truly believe the admissions committee really takes into heavy consideration what a student's major is when looking at GPA, but just the number.
All in all USU's online program has made it possible for me to become an SLP : )