system
8
Most people do not use WD as resident, or depending on your OS do not have it installed (older machines). I personally do not use it because it is a resource hog. Avast and MBAM work fine for me as well as the other security software mentioned in my Signature.
There is no know conflict with Avast and WD, but I do not see a reason why you would need to use it, especially with other security software with better detection rates like MBAM.