DP to me means you keep the hens for eggs, and kill the cockerels for meat.  Which means you want them to grow out quickly, because once they get their crow on, cockerels are a big pain in the butt.  That means a lot of the heavy breeds aren't particularly good, because they grow too slowly - Brahmas for example, they do get big and heavy but it takes a long time before they put on much meat.  Of the breeds I tried, Delawares were clearly the superior meat birds, and the pullets are great layers as well.  So I'd say they are the best DP if you want both uses from a single breed.  The cockerels tend not to be mean, which is also a plus.