It’s very difficult to say nowadays is it still maters or not. It’s used to be very important but I’ve heard that PR is becoming less and less important and in the end it would be reduced to zero. And of course you should pay attention to it.

If you're talking about making money, most advertisers want a site with a high Alexa rating and won't look at PR. I've seen many sights with a high PR but not even registered on Alexa because their traffic is so poor. From what I've seen, PR seems to be more for bragging rights and ePeen measurement between webmasters. You may have a high number, but it doesn't mean you have any traffic or true customers that like your site.