In my opinion, a good belt is a must for IWB carry, and goes hand in hand with the holster you choose. A good belt holds the gun tight and secure to your side with no wobble. This was my rig "new" from Milt Sparks:
The belts are a little stiff for a couple days, but very comfortable once broken in.
I use the Crossbreed Supertuck for my 5" Kimber. I like it for it is very thin and is very adjustable. I paid about 65.00 for it. It spreads the weight and is stable like the other holsters shown. You can read more about Crossbreed on other threads posted here.