dchew: "Accurate focus, especially with wide angles is a big struggle for me."
Yup, for me too and especially when those short, wide lenses seem to focus 'beyond' infinity. When my alleged mind thinks of it, I use the Canon 90-degree, magnifying viewer on its 2.5X setting to focus. That really helps.
I'm excited about the Zeiss 21. In my 1Ds years (that ended a couple years ago), I had 2 Zeiss Contax Distagon T* 28s--an F2.8 briefly; it was too 'little'--and then an F2 for quite a while. I LOVED the results of the latter. I now have 17-40, 24-105, and 70-200 (F4/IS) Canon zooms, but the gadgetfreak in me yearns for the Zeiss 21. The 21mm Z/C Distagon T*s sure are expensive at over U$2K, so I suppose the new (ZE?) Canon-EOS-mount series also will be.