If you have overbright or anti-aliasing turned on in game (it's very hard to tell from JPG screen shots taken inside) try turning them off then update your video drivers (if you have an ATI card try the Omega drivers).
The glitch is caused by a z-buffering error in the drivers. Mine have a similar issue where I see little black squares in the distance (as well as my RSI display in the inventory not drawing correctly) due to the order certain things are drawn by my driver.
Basically your video card is having maths errors in deciding which texture is in front. So when it gets a rounding error sometimes it draws the back texture in front. I'm guessing billboards (and some doors) also look screwwy for you.
If new drivers don't fix your problem then I'm afraid that it looks like your videocard needs an upgrade to fix the problem, as the card doesn't properly support directX 9.0c.