I'll definately give K&D a big recommendation. I use one of their tuckable IWB and a belt, both of which are excellent quality and of the utmost comfort.
I'll add a few:
Great stuff, I absolutely love their ammo pouch.
Great holsters readily available. Not the most ornate, but very functional for fair price with lots of styles.
is a great place to get Galco and Bianchi holsters, both companies are great for non-custom orders. I use one of each.
I love the JIT Slide from here. Sturdy, durable, and cheap.
These are some I've looked into, but not used personally.
I've recently come across DM Bullard
and have been thinking about ordering a new holster from him. Haven't decided just yet if I "need" one.