To be honest I can't decide on just one. I প্রণয় them all to put only one as 'the best.' In each song, she portrays it fantastic and fits in the style of the music. In প্রণয় story, she's a beautiful Juliet needing her Romeo. In আপনি belong with me, she plays a very believable unpopular girl. Each song she has done, she fits her personality in it somehow and she sings with joy, প্রণয় and passion for each song.
AAH! প্রণয় Story is so overrated! It's so annoying how people say that it's Taylor's best song! I mean yeah, it's amazing, but there are lots better! And I think "Ours" it's really cool... too bad that it's not really জনপ্রিয় :(