I have a similar setup, albeit a differant cart... and after about 6 years wrenching on my jeeps frequently, Ive developed a system
I THINK works quite well...
I have a metric shit tonne of loose sockets, and open end wrenches, many of them 3 generation old craftsmen, many of them duplicates, or slight variations, so ive given up on organizing them, they stay in seperate containers for when I need them.
I do 75% of my wrenching out of a 99peice husky wrachet/open end set, as it has MOST of what i will need when working on minor repairs, and its very convienient to take the whole case down to the jeep at the street. I can open the case, and find any size socket in 2 seconds... When the case gets old, and doesnt quite grasp the sockets so well anymore, i retire them to jeep duty(I've got the same set in all 3 jeeps)
Whenever i wrench at a friends house, it allways starts out using his sockets/etc, then within 20 minutes, i get so damn tired of looking for the socket I need, that i goto my car and get my socket set, and appreciate the system Ive got at home.
I just do not like those socket rails.... heres a link to the socket set i use... I started out on like the 69peice set, but it skips too many sizes, which annoys the crap out of me.
http://www.amazon.com/Stanley-92-839-Chrome-Etched-99-Piece/dp/B000LY5AKU
Hope this helps, happy wrenching.