I actually tend to think that having JHH at the helm of AMD would have resulted in a completely different AMD to what it is now. nVIDIA and its vision/projects would have complemented AMD so much better along with improved marketing of its tech/features/products.
Just on the top of my head:
-nVIDIA's nforce brand for AMD systems having a strong image (much much better than nvidia's intel counterparts) making their "platforms" stand toe to toe with intels atleast on the marketing side of things.
-nVIDIA's ambition into the mobile space would have changed focus for AMD and i.e. not sell off its mobile division to Qualcomm.
-The emergence of HPC market meant that the opterons complement very well with Tesla based products. (AMD sort of does well in server side of things). Not only that but investments into CUDA/OpenCL makes AMD a very strong player here.
-Professional/workstation products e.g. quadros also give AMD a good boost and further builds up its image in the industrial/professional market.
-The CPU/GPU combinations matches well (given all scenarios) giving customers more flexible options in terms of price (bundling).
-Much stronger image/brand recognition!
Some food for thought.. I mean both even share the same colour scheme ala green!