I'll add some of my favorite Friendship is Magic based YouTube videos too I can only think of these at the top of my head, but I'll add more when I find them.

Don't Stop Believing, My Little Ponies! - YouTube One of my favorite episodes set to one of my favorite songs. Very well edited, quite touching.

DISCORD (PMV) - EuroChaos Mix (HD 720p) - YouTube Fanmade music video, awesome special effects in the editing, great song. Also great editing.

Fluttershy sleeps, while I play fitting D'AAAAWWWW music. - YouTube Just a picture with a song playing in the background, but I simply love this video and just between you and me,it actually makes me feel really emotional for some reason...

My Little Bloopers: Mistakes are FOREVER! Vol.1 - YouTube The first of an entire series a look at various errors in Friendship is Magic but it is very entertaining, barring contant uses of troll faces in some episodes (which I only know as an underused DeviantArt hoax). There's also hidden images in some the videos (some not exactly "nice" imgages in some of them) I hope you have look at it though .

If I find/think of anymore I'll add them