Over the years I've accumulated a number of camera bags, but with a little application I managed to make 2 redundant, and focus the remainder for specific photographic needs. First of all, I put my main landscape kit into my Billingham 550. Now this bag can swallow a whole load of gear, and the consequence is it can get pretty heavy. But, for most of my landscape work I'm not generally walking far, and I'm not rushing, so the weight of a Nikon D3x, 3 tilt-shift lenses, filters etc. is not really a problem.
At the other extreme, I have a small Billingham Hadley, which just about accommodates a Nikon D7000, Tokina 11-16mm, Nikon 35mm f/1.8 and a nifty 50 (more on this shortly). This is just perfect for casual carry-around work. It's small, discrete and works superbly well, and will even accomodate a D3-sized body (with lens removed) and a standard lens.
For wildlife, my other main photographic interest, I have a Lowepro Dryzone rucksack. This swallows a 300mm f/2.8, teleconvertors, 70-200mm and 105mm macro lenses, and remains comfortable even with all that weight. I'll pack a D3 or D7000 with this depending on the size of the subject and light conditions.
Now that I have focussed (pardon the pun) my gear into 3 distinct setups, it's thrown up some anomalies. First of all, I realised I had collected 4 'standard' lenses: a 45mm PC-E tilt/shift lens, a manual focus 50mm f/1.2, autofocus 50mm f/1.8 and a manual focus 55mm macro. The 45mm was a given in my landscape work, but of the other lens I was finding critical focus at wide apertures tricky on the 1.2, and although the AF f/1.8 kind of worked, it wasn't really comparable in image quality to the 1.2 at these wider apertures on full-frame. The excellent 55mm macro has practically been superseded by a 105mm AF macro, which has a more practical working distance for macro work.
So, in the end I am selling on both the 50's and the 55mm, and replacing them with the new Nikon 50mm f/1.8 AF-S G lens. I tried the f/1.4 version but found the bokeh 'noisy', and actually preferred the slower lens, which takes it's place in my carry-all-day kit bag. Less to carry, less to store, more money in the bank. I will no doubt miss some aspects of the f/1.2 and the 55mm, such as build quality and a certain tactility that modern lenses don't give you, but the new lens simply seems a more effective (efficient?) tool for the job.