NVDA and AMD - worth it now? Which one?

$NVIDIA (NVDA.US)$ $Advanced Micro Devices (AMD.US)$ Considering buying one or both and holding for the long term. Would you buy NVDA today at $240? What about AMD today at $120? Waiting around for them to drop seems like trying to time the market. I will likely buy both, but if you had to choose one of them, which would you choose? Thanks!