For casual wear, I like to use the Wilderness Tactical Instructor belts, 5 stitch. My first one has the original metal buckle, but next one I bought has the plastic buckle. For a dressier belt, most of the custom leather holster makers also make belts. My leather belt was made by Little Bear Leather, but they're out of business. The "Double Duty" belt from Cabela's is not too bad. These leather belts are THICK, as they should be. I'm always surprised to see postings on the 'net where someone complains about their leather gun belt being "thick" or "stiff." I have 2 leather belts that were free from LA Police gear. They're ok, but not as good as the others already mentioned. Google custom leather belt makers. A good custom leather belt for holster carry will run you upwards of $50, but it will be money well spent.
The only belts I've used that I like better than the Wilderness "Instructor" belts are those made by The Beltman
. IIRC he's in North Carolina.
I guess these qualify as "custom made" since he needs a specific length measurement (explained on his website), a specific width, hole spacing choice, color, and choice of material.
I was very pleased with the first (bullhide) belt I bought -- later bought a horsehide belt that is even better (stiffer).
I think the cost is ~ $70. They last forever.