No, you should not. Ether became a stabile cryptocurrency with an entire network behind it that offer many features and has other advantages in comparison to the other altcoins. Besides that, you shouldn’t sell your Ether for Bitcoin Gold since the Bitcoin Gold is probably not something worth investing for.
Currently, there is a drop in altcoins, since everybody is selling their currencies in other to buy Bitcoin which will allow them to get free Bitcoin Gold. Also, there are many concerns about Bitcoin Gold being a “scam”. That is certainly not true, since the Bitcoin is creating a hard fork – so, there is a background to it. Either way it is difficult to give reasonable presumptions about the future of Bitcoin Gold. Most of the analysts disagree with a positive outcome of Bitcoin Gold.
Another important question is – does BTC Gold represent something necessary on today’s market? Certainly it is not. There is already a cryptocurrency called Zcash which basically has the same algorithm that Bitcoin Gold is intending to use. Also, there is still no wallet for Bitcoin Gold which may become a problem. There is another hard fork, it is a Bitcoin Segwit 2x. Many people on the market see more prosperous future for this project that will allow increase in block size and solve many debates about Bitcoin future.
Ethereum as a platform will continue its steady rise and I believe that selling it for Bitcoin, just in order to get Bitcoin Gold, is not a good idea at the time. Bitcoin Gold is developed in order to decentralize mining authority that regular Bitcoin currently has. Anyway, Bitcoin by itself is always a good idea since through years it showed capacity to overcome crashes and it became acknowledged worldwide. Simply, at this time it is not a good call to sell ETH.