I posted a thread earlier with the song by Wilson Phillips - Hold on For One More Day.
I also have Stand by Rascal Flatts - http://www.youtube.com/watch?v=tneHF7M0TS8
and
I Can by Joanna Stahley (yes, the theme song for the show Ruby), I couldn't find an official video so this is her doing it live -
http://www.youtube.com/watch?v=5_uj2YcVEuM
What songs have inspired or motivated you during your journey?