I do love Penguindrum.
My top 5 (there may be some nostalgia glasses):
1) Higurashi no Naku Koro Ni
2) Kara no Kyoukai
3) Bakemonogatari (actually the whole series besides Nise)
4) Elfen Lied
5) The Melancholy of Haruhi Suzumiya
Some other honourable mentions: Steins;gate, Madoka, Fate/Zero, FMA Brotherhood, Toradora, Evangelion, Azumanga Daioh...
Re: Penguindrum
1. I liked the first season, but the second was a huge step down in quality.
2. I've only seen the first three movies, and am not a fan. It's way too confusing at this point, but that may change once I finally watch the remaining 4 films. Aside from that, I don't care for Nasu's style of storytelling. It's a miracle that I liked the F/SN visual novel.
3. Love it.
4. I liked it when I first watched it, but I'd probably hate it now. The manga had its moments, though. The ending in particular was much better than in the anime.
5. Between the two TV series, I liked about 2/3 of it. The other third contains Endless Eight and a few one-off episodes from Season 1. I watched it in my first 6 months of watching anime, so I'd probably like it more now that I will actually understand most of the references. The movie was great
I haven't seen Azumanga Daioh yet, as I want to finish its manga first, but all of your other honorable mentions are 7s or 8s.
My top 10:
FMA: Brotherhood
Kaiji
Code Geass
Fate/Zero
One Piece
Death Note
Steins Gate
Legend of Galactic Heroes
Parasyte
Monster
So, Kaiji aside, pretty conventional stuff. Now, about controversial opinions:
I bolded the ones I liked. I have no intention of ever watching One Piece, and didn't care for the remaining titles.
I only have a solid top 6, but my top 10 would look something like this:
The Tatami Galaxy
Shinsekai Yori
Mawaru Penguindrum
Kaiba
Welcome to the NHK
So Ra No Wo To
Gunbuster
Hyouka
2 of Revolutionary Girl Utena, FMA: Brotherhood, and Serial Experiments Lain
Highly rated animes that i didn't like: Evangelion and AnoHana.
Highly rated animes that i only found decent: Angel Beats, Tengen Toppa, Hellsing Ultimate and Cowboy Bebop.
I'm right with you on AnoHana. But NGE, though... I admit that my love for the series has partially diminished since I first watched it, but End of Evangelion still gets me every time, and Asuka is my all-time favorite anime character. Are your feelings towards it closer to indifference or dislike?
Oh yeah how did I forget Code Geass?
I wish I could forget Code Geass.
...and there's my most controversial anime opinion. It's very rare for me to absolutely despise everything about a work of fiction and what it stands for. This is one of those cases. It's the only show of its length I regret watching all the way through.