I didn't know that this thread was over ten years old! In honour of our departed Roger, I'll add my comments.
Like just about everyone, I began with just one camera, and the lens that came with it. In my case, digital began with the Canon S45, and I carried it everywhere. It was good for its time, but tech has moved a long way since those 4mp days. As time went by, I bought more and more cameras, eventually going into DSLR's, rangefinders and mirrorless. Now, I'm never without at least two cameras, the type depending on anticipated shooting conditions.
Canon S45
S45 - Trainstation Fullsize by
Archiver, on Flickr
The issue for me is finding a balance between versatility and size. The Canon 5D Mark II with 24-105L does just about everything you want, but I'm done with carrying gear like that every day. A Leica M or similar sized mirrorless camera is far better, but even that can become a bit large after a while. Now, I carry a Sony RX0 which goes in my pocket, and the secondary camera is either a m43 camera like the Panasonic GX85 with a couple of small primes, or the wonderful Contax T3.
Sony RX0
RX0 - The Light of the Times by
Archiver, on Flickr
Contax T3
T3 - Taking Flight [explore #177, 2007 02 07] by
Archiver, on Flickr
Do I worry about gear failing? I can count on the fingers of one hand when gear has stopped working - unfortunately, three of those fingers are taken by Ricoh - so I'm not overly worried about it. If I'm shooting for work, I'll have a backup body anyway. Personal work is usually a couple of pocket cams, or I'll go with the M9 when I want the best quality.
Leica M9 with Summicron 50
M9 + M50/2 - Waiting by
Archiver, on Flickr
As for lenses, I'll carry a 24 or 28 and 50 when I can, or a fast 35 when I can't.
@Ko Fe - you've inspired me to shoot with the M9 and Voigtlander 35mm f1.7 LTM for a while!