For me the flying batlord set 2848 was a better set then the other shell promotional flying batlord set 2539 at least it contained traditional weapons. I passed on buying the witch ship:
http://www.bricklink.com/catalogItemPic.asp?O=2539-1
I don’t think the fright knights theme was that bad you just have to accept the magical/dragon/witch castle premise?
For me the fright Knights contained good minifigure torso designs, it was KK2 that I disliked, the use of soft pastel colours and jelly bean minifigures.
The colour combinations in the fright Knights (Black, Brown, Dark Grey, Light Grey with red and yellow highlights) were actually as good as anything that came before them in my opinion.
The worst castle set in my mind:
http://www.bricklink.com/catalogItemPic.asp?S=8801-1
What that assault ship powered by diesel?
Not to sound totally anti KK2 I think the last sets like battle of the Pass and Rogue Knight Battleship and the blending of KK2 and KK1 elements in Royal King's Castle were good.