There are many suppliers these days, and an offering of many fine products to choose from. I'm still using the same old equipment that I've been using, and can't really justify getting a new pretty one, when my old ones are still hanging in there though.
I like to use heavy duty canvas bags that won't come apart. My favorite bag is an old news cameraman's bag I found in a thrift store for ten bucks. It's cirica 1990's and made by OGIO, which is a top end manufacturer of assorted high quality bags, and is still in business. I started using Musette bags as part of the Marine Corps pack system, to replace the "Butt Pack". They've been around since WWII, and you can still find them in Surplus stores, and reproductions are sold online. I have some heavy canvas tool bags that linemen use for pole climbing, they are good for tools, ammo, & heavy stuff. Pretty much impossible to rip one apart. All these bags can be loaded to the point that they are too heavy to easily carry, and still won't tear or come apart. I still check out thrift stores for bags, and some of the better finds are pre digital camera bags, when people carried big heavy lenses for their SLR's. They are padded & usually well made too. Here are some pics of mine, I'm sure there are some out there that are much nicer.