1 Pinkie Pie
Try to google "smile song" and you'll easily know why she's first in this list
2 Twilight Sparkle
she gives the books to everyone!
3 Applejack
Can't really find anything, only the welcoming she gave to Twi when she came to Ponyville
4 Rarity
5 Rainbow Dash.
Best pony, but she's clearly the least kind one.