If you have improved your status as an applicant, by all means reapply to as many programs as you want. Things change, including the applicant pool, both in quality and numbers. The fact that you got waitlisted last year means you were really close. Remember that at least one more program will be up and running for the entering 2012 class of students.
Get all your materials submitted and let them know another GRE score will be forthcoming. I don't know if they maintain the application materials from last year but make sure that you have everything submitted and don't get tripped up by a missing LOR or something minor.