Find a holiday sale or Cyber Monday deal on a 70". I agree you should not concern yourself with 4K yet, OLED appears to be expanding through manufacturers for 2016, so within a few years we should see some very competitive pricing.
Til then, 1080P looks spectacular, particularly when using a quality player like an Oppo. My older BDP-93 provides noticeably superior video quality, even on my 'puny' 42" ;-)