Old - Jenkins wrote...
UBW Arc from
Fate Stay Night
VERY TRUE
Negima: School Festival Arc (Which, btw, was never animated because it's too awesome for the anime which really, really sucks)
Double Arts: The beginning to when they find their own style, "Double Arts". It's not officialy an arc due to damn japanese kids, but it still is awsome
Yu Yu Hakusho, Flame of Recca: Tournament Arcs
Naruto: Sasuke Retrieval Arc (the only thing I have and will like about Naruto. The shippuuden anime never happened for me)
One Piece: Water 7 saga (Yes, SAGA. It includes from when they met Admiral Aokiji. to the epilogue at water 7 Arc) Possibly the most emotional moment of One Piece, aside from when they left Alabasta and and when Chopper saw the Sakura bloom at Drum Island when he left
Bleach: Soul Society Arc (The rest never happened. For me, Bleach ended at Soul Society Arc)
Rurouni Kenshin: The time when Shishio invades. Sorry, forgot the name of the arc...
I think it was named Kyoto though
I'll add more if I remember more