Planning on my next toy......

(Since I have promised my wife no new lenses in 2011, I will hold off for now, but doesn't mean I cannot do 4 months worth of research )

Would you go for the 17mm version? or the 24mm version?

I will use it mainly for landscape, and amount of details recorded and sharpness would be my first priority. I have read both reviews but neither can give me a definite answer.

Also want to check is it true that auto focus would be completely out of story?

Apart from Architectural and Landscape, what other subject would you use your Tilt Shift lens?

Thanks in advance for your opinion.