I've never had so many shows on my plan-to-watch since I started watching airing anime, so this autumn has to become fantastic :3
Arakawa Under the Bridge x Bridge: Liked the first season, especially after the introductions were done. Should be very enjoyable when it keeps up its hilariousity.
Fortune Arterial: Akai Yakusoku: Sadly the anime lost the game's character design's charm, but might still be interesting.
Kami nomi zo Shiru Sekai: The manga was very funny for those who are familiar with Eroge, but because of this I expect to be disappointed by the anime, starting from the voice actors ...
Koe de Oshigoto (OVA): MOSAIC.WAV's fully censored OP song will be fun enough to watch it
MM!: A fetish series, the character design didn't do justice to the LN's one, I hope the cosplay action comes well
Motto To Love-Ru: Sairenji & Kotegawa, what do you need more =)
OreImo: High hopes on this one, I absorbed the first novel, reading until 3am XD
Otome Youkai Zakuro: Don't know why I wanted to watch this.. I think it's Horie Yui voicing some awesome drills
Pokemon Best Wishes: The Pokemon series has matured, DP just had a fantastic battle, the games are better than ever. Will watch
Ika Musume: It was nearly an internet meme that Iguchi Yuka will voice Ika, and in the end she doesn't ^^ - the PV looked good
SoreMachi: As a SHAFT-fan, this is also the insider tip for the autumn
Yosuga no Sora: I forgot what this one was..
Still ongoing series:
Tsurara TV Nurarihyon, Amagami SS will depend on the next arc, I didn't like it really.