hello i have a 4790k i7 cpu
recently my graphic card died so i am looking for a new one.
should i wait for new generation graphic cards or buy a 1060 6gb..? main usage of computer is gaming also budget is around 250-400$ so let me know what you think..

Wait for new gen if you can last that long 100%

A lot depends on what games and at what resolutions.

A 1060 6gb will last a few years if you're only doing 1080p60 gaming. If you want to go higher, either get a 1080 and that will last quite a while, or get a 1050 ti and upgrade next spring when new nvidia cards come out.