I'm not a Buddhist but most of my favourites are from Buddha, such as
"No one saves us but ourselves, no one can and no one may, we ourselves must walk the path" and
"Peace comes from within, do not seek it without"
Then the whole book of The Prophet by Kahlil Gibran, basically a bunch of poetries that explain the philosophy of life. Lastly, my personal favourite is
"Keep moving forward" -Walt Disney
from the movie Meet the Robinsons, it keeps my inside child-like spirit burns