I think I have about 15 or so bags ? but I do photography for a living
and have been at it a long time I agree they vary on the job !
when I lived on Maui I shot underwater for 15 years my main bag was a backpack or a cooler
I shot interior Architecture for some time and also did a lot of resort style work my bag was depending on job sometimes small sometimes big on wheels
my interior arch gear was a SUV full of hard cases
my wedding gear was either a rolling bag (big wedding) or belt setup smaller weddings (Kinesis)
I am shooting less these days and doing more post production for others but I use a 1510 for work here so I can lock it up securely a couple other pelican cases I quit using since I dont shoot huge jobs anymore and I use them for camping
a few thoughts on the coleman cooler as a bag or a bag protector you can just drop your current bag into
offers great stealth
most people dont steal food and coolers at the beach out of the back of cars etc.. they tend to just leave them alone !
great sand dirt protection since its solid and opens up top ! gives you a place to stand on and sit on change lens etc. if you need to the coleman ones with wheels roll even on sand somewhat
and very well on most other surfaces ! can keep your gear a bit cooler on hot days
really a small one for my M4/3 gear in our rig might be just the ticket ! use a lunch size one and chances are it will never be looked at as GEAR !! then again I usually have 3-4 other pelican cases
ahhaahahah
but for shorter day trips etc.. really they are a great option
when shooting underwater was very common to see them on the boat !! store your gear and fill it up use it to rinse the gear etc..