At least, this is how my collection breaks down...

DVD-Sized: Angel Beats (Aniplex), Bakemonogatari (Aniplex), Kiss x Sis (King Records), MM! (Media Factory), Ookami-san to Shichinin no Nakama Tachi (Media Factory), OreImo (Aniplex), Shukufuku no Campanella (Marvelous Entertainment), Sora No Woto (Aniplex), To Aru Kagaku no Railgun (Geneon Universal), Tamayura (SHOCHIKU/Wint) & ToHeart 2 AD Next (Frontier Works).

BD-Sized: Clannad (Pony Canyon), K-On! (Pony Canyon), Hayate no Gotoku (Geneon Universal), Higurashi no Naku Koro ni Rei (Geneon), Kanon (Pony Canyon), Mayoi Neko Overrun! (Geneon Universal), Nanoha Movie (King Records), Yosuga no Sora (King Records), & Yoku Wakaru Gendai Maho (Geneon Entertainment).

Odd-Sized: Shukufuku no Campanella (Marvelous Entertainment)

All LEs. Basically, in my BD collection, everything is DVD-sized unless published by Geneon or Pony Canyon and sometimes King Records. Your collection may vary.