Hard question as I'm still trying to compile a list that is fair to my tastes. This is what I have so far.
1. Tengen Toppa Guren Lagann
2.
3. Nisekoi
4. Angel Beats/Charlotte
5. Hibike! Euphonium
6. Jojo's Bizarre Adventure
7. No Game No Life
8. K-On
9. Magi
10. Love Live/Idolmaster
To be honest this list could easily change depending on my moon or things I've recently watched. The first, third, fourth and fifth spots probably won't change. I really like those shows, they affected me greatly when I watched them. Specially Nisekoi, that show helped me through a hard time. But I don't feel it's good enough from a show story stand point to get the number 2 slot. The number 2 slot is empty for the next great anime to come.