The belt is the final part of the rig I am trying to nail down. I've arrived at the perfect gun and holster, but the belt I am still working on.
I started with a 5.11 Double Duty TDU, like RM08 mentioned above. It is a great belt and I still wear it often. However, it doesn't pass the "stiffness test", which is generally trying to fold it in half the hard way (like a taco). You shouldn't be able to do this with your hand strength, but its fairly easy on the 5.11. However it is still stiffer than most "normal" belts, and its good enough for a relatively light gun with nothing else on the belt. If I am carrying a full-size gun, or the addition of reloads, it starts to show its weakness.
I then got a custom leather belt from thebeltman.net. These are highly recommended all over the Internet, they are handmade in Apex, NC, where I actually just was last month for a wedding. Anyway, these are very thick, incredibly stiff, beautifully made belts. It passes the stiffness test above. I ordered it for my correct pants size, with an extra 2" to accommodate the width of the gun. Using the center hole which is sized that way, it is comfortable. However I don't quite conceal as well as if I get it really tight. Using the next hole in accomplishes this, but its very tight and not comfortable. I find that if I use the 5.11 belt, which is infinitely adjustable, I can find a happy compromise which would fall between the two holes on the leather belt. In the winter, I could probably get away with the looser setting, but with just a t-shirt in the summer, I really need that last bit of carrying tighter against me.
So, I am currently seeking an infinitely adjustable belt that is stiffer than the 5.11. I am planning on buying one of VRI Tactical's EDC belts (
Clothing > VRI Tactical > VRI Tactical EDC Belt) at the next gun show. In the mean time, I can recommend the 5.11 especially due to its price, and the beltman belt if you are ok with 5 settings and the possibility of needing to pick one that is too loose or too tight.