Well....i got lucky as one of my site gained a PR of 3 during this update without having any backlinks and also the site was launched only in May 2008.......But the downfall was the site which i was promoting has not changed its PR...Also it showed me my site PR will go to 6 from current 5 in PR predictor....
PR is very important if you want to sell links . a pr4 page can easily make $60 a month by selling links and if your website have thousands of pr pages your income can cross $$$$ ..So ignoring pr is not right .Also most of the 1st page/2nd page sites in google have good pr (for almost any keyword) so importance of pr (backlinks) cannot be ignored on SERP point of view . Well just keep working on link building , your pr may go up in next update . PR fall PR up is a continuous process