There's a powerful argument to be made that the most effective, minimal system would consist of just on Lumix S1 body and the 24-105mm f4.0 Lumix lens... It's pretty self-contained.

The buying philosophy I seem to adhere to...

Not really an oppressive package to haul around. The kit lens is lighter than it looks. 

Love being able to go from wide (above) to tight (below) without a lens change. 

Nothing really amazing but when I blow stuff up and become a pixel peeper in Photoshop I am impressed by the sharpness and resolution of the 24-105mm lens. Maybe I should have just stopped there?

Some samples from the Sigma 20mm f1.4 Art lens when used on the Panasonic Lumix S1. Nothing very formal. No tripod required.

I've been photographing as a career for decades, have written a number of books about technical aspects of photography and also do it as a hobby. But I'm still trying to learn how to use ultra-wide angle lenses better. I know, we're supposed to put stuff in the foreground, etc. but my brain just doesn't see the logical answers to the visual puzzle with so much going on in the frame. But I bought one of those lenses wide angle lenses anyway. And now I'm trying to learn enough tricks to rationalize working with one. It's by no means my first wide angle but regardless of pedigree or specs the wide view still leaves me cold. Tips always welcome. 

Anyway, here are the wide images I shot on my walk around the lake and through downtown today. Maybe we can salvage something?  It is sharp and I don't see any real issues.... but.....