Tier Definitions:
S: Absolute must-watch anime. If you have not watched these you should definitely watch them.
A: Very good shows. Make a point of watching these, but they are not quite on-par with the stuff in S. S-tier anime which is unappealing to certain types of viewers is also included here (such shows are indicated by †)
B: Good shows. I recommend you watch them, but if you choose to skip them you wouldn't necessarily be missing a must-watch anime. Also includes shows which are of A rank quality but unappealing to certain types of viewers (such shows are indicated by †).
C: Okay shows. These are solid watches that either appeal to some types of audiences but not to others or that . Watch these if you're interested in their genres. Shows that are "so bad they're good" also come under this category (such shows are indicated by †).
D: Borderline OK shows. These aren't complete wastes of time to watch, but in my opinion people giving major credit to these shows either lacking anime experience or poor taste.
E: Poor shows. You probably shouldn't bother with these. Not irredeemably bad, but not good watches either. Bad without entering "so bad it's good" territory.
F: Bad shows. These shows are irredemable. Avoid them like the plague.
Key:
*currently airing
†indicates certain category of show (specified in definition for the respective tier)
¶the show is heavily overhyped
Tier List
Disclaimer: if a show is not listed, it means that I have not gotten around to watching it yet. There are a number of shows on my "plan to watch" list that are not listed on my MAL, such as Stein's;Gate. In addition, shorts and Pokémon have been omitted to prevent unnecessary inflation.
"New" Rank (shows I have started watching but have not seen enough of to comment on):
- Death Note
- Yamada-kun to 7-nin no Majo (Yamada-kun and the 7 Witches) - read what's been released of the manga though and am really liking it
- Tokyo Ghoul
- Shirobako - I've heard from others that this is S material, but I've only watched ep. 1 so far
S (ordered):
- Boku Dake ga Inai Machi (ERASED)*
- Ano Hi Mita Hana no Namae wo Bokutachi wa Mada Shiranai (anohana: The Flower We Saw That Day)
- Mahou Shoujo Madoka★Magica (Puella Magi Madoka Magica)
- Toradora!
- Sen to Chihiro no Kamikakushi (Spirited Away)
- Howl no Ugoku Shiro (Howl's Moving Castle)
- Tonari no Totoro (My Neighbor Totoro)
- One Punch-Man
- Suzumiya Haruhi no Yuuutsu (The Melancholy of Haruhi Suzumiya)
- Fate/Zero
- Hai to Gensao no Grimgar*
- Fate/Stay Night: Unlimited Blade Works
- Ajin*
A (ordered):
- Non Non Biyori and Non Non Biyori Repeat
- Akira
- Hibike! Euphonium (Sound! Euphonium)
- Musaigen no Phantom World (Myriad Colours Phantom World)*
- Dimension W*
- Jinrui wa Suitai Shimashita (Humanity Has Declined)
- No Game No Life†¶
- Selector Infected WIXOSS and Selector Spread WIXOSS
- Angel Beats
- Rokka no Yuusha (Rokka: Braves of the Six Flowers)
- Mahou Shoujo Madoka★Magica Movie 3: Hangyaku no Monogatari (Puella Magi Madoka Magica: Rebellion)
- Shokugeki no Souma (Food Wars! Shokugeki no Soma)
- Bubuki Buranki (BBK/BRNK)*
B (ordered):
- Dungeon ni Deai wo Motomeru no wa Machigatteiru Darou ka (Is It Wrong To Pick Up Girls In A Dungeon)†
- Schwarzesmarken
- Charlotte
- Shingeki no Kyoujin (Attack On Titan)¶
- Inazuma Eleven
- Inazuma Eleven Go Chrono Stone
- Glass no Hana to Kowasu Sekai (GAROKAWA: Restore The World)
- Inou-Battle wa Nichijou-kei no Naka de (When Supernatural Battles Became Commonplace)
C (not ordered):
- Kono Subarashii Sekai ni Shukufuku wo! (KonoSuba: God's Blessing on This Wonderful World)*†
- Active Raid: Kidou Kyoushuushitsu Dai Hachi Gakari*
- Sword Art Online II
- Inazuma Eleven Go
- Genai wo Kakeru Taiyou (Day Break Illusion)
- IS: Infinite Stratos†
D (not ordered):
- Sword Art Online
- Inazuma Eleven Go Galaxy
- Ao no Katana no Four Rhythm (AOKANA: Four Rhythm Across the Blue)*
E (not ordered):
- Gakusen Toshi Asterisk (The Asterisk War)
F (not ordered):
- World Trigger
- Infinite Stratos 2