Last year when AMD showcased Vega on its roadmaps, many assumed that this is will be the HBM 2 card and they were right. There is an HBM 2 card based on Vega architecture that should attack Nvidia in the high-end space.
But there will also be other cards, as Vega hits other memory interfaces and not just the HBM 2. You can expect to see GDDR5 variants too. Our sources had no information if there will be GDDR5X card based on Vega architecture but it would not surprise us. Nvidia made a good product using this type of memory as it sits at the right price/performance ratio.
AMD is missing a high-end card to put some pressure on the ultra-high end and the Titan X and Geforce GTX 1080 market. From the first Doom results, it looks that the Vega high-end solution is the right card for 4K gaming at over 60 FPS at least in Doom with the Vulkan API.
Knowing Nvidia, the company named after a Roman vengence demon is not sleeping and is working on its 2017 line-up.