What about your budget ?
the best is 1080TI but 1070 is also good.
Red 56th vegas also great
For small budget for now good modded RX550 cards for mining cryptonight and eth forks
i have a large budget and want to get the best possible cards ,i just love the mining aspect of crytpo any end profit is a bonus
Then what about wait and buy new ASIC F3 on GDDR3 memory, if you love only GPU mining rigs then create from 1080TI and VEGA 56/64
Buying a vega 56 or 64 is false economy. They do not produce enough for what they cost. The only thing they are good for is if someone has limitations to the amount of cards they can support with motherboard(s) or power supplies. In those cases stuff your rig(s) with Vega 56/64.....if you have the money for those AND have limitations making you have to go that route.