First of all, it's been announced that PageRank is the "heart" of all Google technology. It can be found in here. So I think it's not really an good thing to ignore it.

Very true; However the PageRank that is at the "heart" of Google technology is NOT the same as the PR value that is shown by the toolbar.
It is this fact that we keep tying to get over to people. It is the toolbar PR that is a useless value.
The REAL PR value is only one of over 100 factors that make up the ranking algo
http://www.brianwhite.org/2007/06/25/i-have-pagerank/

Yea. Just read about it that the ToolBar PR is not really updated but it's "export" from the Google's data center. Thanks for pointing it out!

As some put it - PR is nothing more than a show off, lols Which is kind of true in certain context.

IMO, better focus more on SERP as this is where SE traffic comes from