I haven’t noticed any dust problems with my 30D under normal use (I pretty much always shoot faster than f/8) until one day I stopped down to f/32 to try to force a long exposure in bright light and my picture had all these hairs and dust spots in it… Well, the lens I was using was like 10 years old and you can see dust and hairs inside it when you look through it so I figured that was what was going on. Until I got the same problem with my brand new L lens. Yup, I’ve got sensor dust. Only had the camera for about 2 months!