Personally I run a chest rig WITH a war belt. Now my belt isn't loaded down like its the only thing I got on but this is how I break it down. (BTW, check out this site by Curahee [sp? {sorry it's WAY past my bedtime and Ive been humping my ass off all night}]
http://everycitizenasoldier.org/id12.html ). I know mine is a little different from his but that is because I separate the first and second line since there are a lot of people out there that do not have a pistol but do have a rifle.
First line (which is the shit in my pockets) is the most basic bare bones gotta have it to survive in the woods cause I don't pretend to be Rambo or Chuck Norris. This is stuff that is included in my current EDC so it is on me at almost all times.
Second line for patrol/guard duty/combat is the War Belt. this is a sturdy belt that goes over my belt that keeps my britches in place. i keep on it the things that if I did not have my chest rig I could easily E&E. Since this is where I keep my secondary (pistol) this is also where I keep the mags for it, on the opposing side of the belt from it. I also keep a spare mag or two for my primary, my IFAK, flashlight, and MT as well as a couple other things I cant remember. Again, the premise behind this setup is to have something to supplement my chest rig in combat, but to have a system in place that if I have to ditch my chest rig or cannot or do not have the option to run a more combat oriented system.
Now remember how I said the War Belt is for combat, etc., etc.? That is because if I am just strolling around the community or maybe tending the fields I will have a different setup for my second line. The premise will be similar but geared more to responding to an immediate threat and withdrawing or holding on till help arrives. This would be a basic IFAK and secondary with mags.
Third line is the "fighting load" with the chest rig, mother load of ammo and anything else that make me effective lead and whoop-ass dispenser. Check out the link above for more specifics, or shoot me an email if you are that curious about my load.