Thanks everyone! I had never planned on taking the psych GRE until recently ($150 + $27 to send scores to each school - That's $555 to send scores to 15 schools), but after I went through my list of schools, I found that there were many more than I had originally anticipated that either require the Psych GRE or strongly recommend it.
The whole process seems a little backwards to me and kind of like a scam - Why should people with undergraduate psychology degrees, published research specific to our areas of interest, and years of relevant work experience have to pay hundreds of dollars to take a test that proves we have a basic understanding of our field's core concepts? I could understand school's requiring people without undergrad psych degrees to take it to prove general competence, but it seems a little silly (insulting?) to require all applicants to take it. I've heard of people who have never taken the Psych GRE being admitted to schools that require the subject test, but I'm not prepared to take that risk, so I guess it's time to bite the bullet and register!