Most exciting division: 154

[killersheep]

Not because of the champions.
Because of abundance of good challengers:

Sergio Martinez, Alex Bunema, Alfredo Angulo, Joel "Love Child" Julio, James Kirkland, John Duddy, Ronald Hearns, Vanes Martirosyan, Joe Greene, Deandre Latimore, Julie Cesar Chavez Jr.

I'll give it the most improved division, no doubt, but Lightweight and Welterweight divisions have both great champions with solid styles clashing as well as upcoming challengers.

I think even though there are a lot of really good prospects and title contenders at 154, I think about half of them will move up to fill the void at Middleweight, just my guess.