Ahoy! I'm new to these forums, but have been a fan of the series for about a year, now. It's awesome finding so much... well... awesome!
Order of mane six from most favorite to least:
Fluttershy, Pinkie Pie, Applejack, Rainbow Dash, Twilight Sparkle, Rarity
Favorite Princess:
Luna
Favorite Villain:
Discord
Favorite Background Pony:
I don't really know if she's my favorite of all time, but I've been into Vinyl Scratch lately.