Taking time to view each and every ending for each and every anime airing in Fall 2008, this list is not simply taken from the shows I'm currently watching. The only cutoff is that the ED has to have just begun this season.
There are a plenty of good EDs this season, though not quite as many as the terrific OPs this season. The ordering could easily change on a whim, but not ranking them would be the sissy's way out!
Update (12/07/2008): And speaking of that whim, I'm now flipping the order around.
10) Kannagi
"Musuhi no Toki" by Haruka Tomatsu
9) Yozakura Quartet
"Nagareboshi" by ROUND TABLE featuring Nino
8) Bleach
"Hitohira no Hanabira" by Stereo Pony
7) Clannad ~After Story
"TORCH" by Lia
6) Soul Eater
"Bakusou Yumeuta" by Diggy-MO'
5) Hyakko
"Namida Namida Namida" by Aya Hirano
4) Shikabane Hime: Aka
"My story" by angela
3) Linebarrels of Iron
"Ame ga furu" by Maaya Sakamoto
2) Toradora
"Vanilla Salt" by Yui Horie
1) Gundam 00: Second Season
"Prototype" by Chiaki Ishikawa