I purchase commercial themes to build websites for my clients but I have to rely on plug-ins to achieve what the customer wants within a particular website. I feel the functionality of themes and plugins go hand in hand. Any one theme will NOT offer the designer 100% of what he needs to build his/her site and that is where plug ins come in handy. Personally I hate relying on custom CSS coding to change the most simple of things and I wish commercial themes would offer MORE options to change the layout of my design.... I am hoping this comes in time.