I prefer the wide end of focal lengths, usually around 28mm (can't afford anything wider) so its the wide end of the DX 18-70 AFS G ED on the digi and the 28-105 AF-D on the film (same focal lengths really). I have a few Carl Zeiss lenses on my old screw thread Pentax Spottie - my favourite being a 35mm f2.4 Flektogon which also had pretty good close focussing. I have a couple of lenses for the Blad, my favourite being a C T* 50mm f4 Distagon (I guess around the 28mm equivalent).

I've never had the opportunity to use anything wider so don't know if I'd get more use out of a wider lens, though I did get to use a 38mm Biogon SWC Blad while at college and quite liked it. Flicking through the latest issue of AP I think I'd have one if I won the lottery (along with a digi back and a D3)