If you work out what you want to grow, based on what you like to eat, your list may or may not include blackberries. You may also find wild blackberries elsewhere for free...
Also you may find theres not going to be enough room for all your yummy crops if the brambles stay.
Its very hard work digging them out, but just as bad digging out ther new suckers every year, its certainly not an easy option to leave them in.
Hope this has helped...