After 3 months I finally caught up in One Piece, and now I have no idea what to watch! Please recommend me something.

Katekyo Hitman Reborn! Because you watched OP I can guess that you like action stuff, that's why I recommend you KHR it's a great anime with much action, comedy and supernatural stuff.
Another good ones are :
Fairy Tail, Black Butler and Fullmetal Alchemist:Brotherhood.

Bleach & Naruto Shippuden

the best 2 leading animes...............he he ehe he

Naruto Shippuden / Bleach

try air gear its cool and funny

have you watched shingeki no kyojin? (haha an obvious response xD) it's amazing and a really strong, emotional anime. A close second would be Another, it's really good too :3
also Deadman Wonderland. Yeah idk hope that helped haha ^-^

You can try Pandora hearts, Guilty Crown and Sword Art Online, are awesome! ^^

Case Closed!!!!!!!!! It is a good mystery series and its super funny.

Well, as far as I can tell, you've already watched Naruto, Avatar: The Last Airbender and Fullmetal Alchemist, so I recommend... Magi. I haven't watched all of it, yet, but I love it almost as much as Fullmetal Alchemist! =^^= It has an interesting storyline, great characters and magic! What more could you want? :P

Also the faces are really cute! :3

You should try Clannad + Clannad After Story, Air, or Angel Beats!. :D


(Clannad in the picture)

I highly recommend you to watch Prince of Tennis because it is the best school life involving tennis anime...It also teaches you many tennis facts,tennis plays,be strong and never give up,great friendship and many more...!!!

BLEACH

If you like one piece watch bleach naruto naruto shippuden
Because they all have something in common
Action
Adventure
Fantasy
Humor
( also they all are popular)

Air Gear

Naruto . It is awesome and my favourite character is and will always be Sasuke Uchiha . I hope he becomes yours too if you watch it .

1. Dragonar Academy
2. Inuyasha/The Final Act
3. Phantom: Requiem for the Phantom
4. Code Geass/R2
5. Cardfight Vanguard/Asia Circuit/Link Joker/G
6. Black Cat
7. Sankarea
8. A Certain Magical Index
9. Fullmetal Alchemist Brotherhood
10. Fate/Zero
11. Yu Yu Hakusho
12. Spice and Wolf/II
13. Rosario + Vampire/CAPU2
14. Fate/Stay Night {Picture}
15. Soul Eater
16. Kaze No Stigma
17. Nura: Rise of the Yokai Clan/Demon Capital
18. D.Gray-Man
19. Witchblade
21. Sunday Without God
22. Rave Master
23. Highschool of the Dead
24. Romeo X Juliet
25. Gargantia on the Verdurous Planet
26. Buso Renkin
27. Maoyuu Maou Yuusha
28. The Legend of the Legendary Heroes
29. The Devil is a Part-Timer
30. Spiral: The Bonds of Reasoning
31. Neon Genesis Evangelion
32. Shakugan No Shana/2/Final
33. Shaman King
34. Magi: The Labyrinth of Magic
35. Dragonaut: The Resonance
36. Infinite Stratos
37. Aesthetica of a Rogue Hero
38. Guilty Crown
39. Historys Strongest Disciple Kenichi
40. Elfen Lied
41. Black Lagoon
42. Digimon Frontier
43. Is This A Zombie/Of the Dead
44. BlazBlue: Alter Memory
45. Muv-Luv Alternative Total Eclipse
46. Marvel Anime: X-Men
47. xxxHOLiC
48. Strawberry Panic
49. Gurren Lagann
50. Air Gear
51. Beelzebub
52. Digimon Data Squad
53. Aquarion Evol
54. Yu-Gi-Oh 5D’s
55. Blassreiter
56. Marvel Anime: Wolverine
57. Rurouni Kenshin
58. Samurai 7
59. Witch Hunter Robin
60. Ikkitousen
61. Accel World
62. Marvel Anime: Blade
63. Sengoku Basaru
64. Blood +
65. Campione
66. Kämpfer
67. Darker than Black

This list was originally done by NeoClaw. Now brought to you by me LOL!