The below are some suppliers we've used and abused over the years.
Cold Steel: For all of the smack we've talked about Cold Steel, item for item, we may use more of their stuff than any other knife and sharpened object supplier. I have an old Vaquero Grande that has been modified into a shoulder rig that I like to use on walks around the block. Keep in mind that their "solid proof" guarantees aren't for all of the knives, as Cheese found out with a closeout kukri that is now suspiciously listed as a "kukri machete." Good thing we didn't need it to behead a sleeping vampire. Talk about embarassment. Like any good relationship it's a little love/hate - after all their True Flight Thrower is the official throwing knife of Orion.
County Comm: They describe themselves as "government products group," but I can't imagine what government agency would really need all of their stuff. Kind of a "Johnson Smith Company" for the outdoors/pseudo-cop/shooting/soldier/gadget geek community, they have a wild set of equipment linked to from a hard-to-navigate website that makes extensive use of the scroll button on your mouse. I've always felt I needed a small grappling hook to go onto my belt kit and they had the perfect product to fit the bill. Customer service pretty much blows (I had an order shipped to the wrong address and they just ignored me until I went away), but if you can stand to deal with them (after all, they are in California), then they have some really cool unique stuff at good prices. Also a great source for the mini-hack saws that are so good to put into e&e and survival kits.
Mike Billman Knives: Mike is a self-described knife geek and master of the kydex sheath. I got a really cool neck-knife set-up from Mike a few years ago and have worked with him on a few designs since that time. Mike helped me build out a "quick-draw" rig for a tomahawk that I designed and makes great "woodslore" set-ups for most knives. He is great at integrating firesteels, nylon cord, and chicago screws into really workable and durable sheath systems. He's got a website, but the real place to see his good work is on eBay.
The Gun Show: Ok, so not a true supplier in the whole "can go to their website" sense of the term, we've probably kitted up more at gun shows than any other source. After you spend $5/piece on BDUs, it's really hard to even look at catalogs for new duds, much less check out an Army-Navy store. A good supply for the average height/average weight crowd, but harder to find a good fit when you start to move out in other directions. B. Knight had to drop a bit more, but his height also means he's usually the one that ends up getting shot in the head. Alas.
For a listing of gun shows, check out the List.