gtx 770 or r9 270x or something else ???

Depends on your budget, GTX770 is much faster than the 270X, but also more expensive.

The R9 270 (non-X) is a more popular card because of its almost identical to R9 270X performance at a lower price, it's probably the best price/performance you can get.
The GTX770 is also a great price/performance card, it's just the price/performance card of a higher class of gpus.

Basically depends on your budget 😉