I am planning to launch a website (niche) optimized for a key phrase which monthly search volume around 60,000. For this key phrase even the first listed site is of PR 0. Now is it a good idea to optimize my new site for the key phrase? Else should I go for a key phrase with more search volume? Anybody please help.
It totally depends on how much effort you put into the site. Taking it to extremes, it is probably pointless in spending a year developing a site aimed at a monthly search volume of 60,000.
I have several sites aimed at keywords with less search volume than 60,000 but they take less than a week to set up. I earn around $5 a day from each of them and the search terms are evergreen with the sites requiring zilch maintenance. That model seems to work OK. It also spreads risk into very varied areas.
But I've spent years developing other sites and I expect, and get, a lot more than $5 a day from each of them.