I made Rose an alicorn (I call them this, I don't know why...) because I wanted her to be able to use magic, but also have the ability to fly. X3; Selfish, I know, but not terribly.
I love alicorns, they're great! Three of my characters are alicorns, in fact. In my version of Ponyland (or rather the whole Kingsley's Board version), alicorns are just as common as unicorns, earthlings and pegasi. ^-^