It seems to me that all sites start out as "google has no pagerank infor about this page". From there you might or might not go to PR0. The root of any domain (but not necessarily any third level domain) will get PR0 unless the domain has been blackballed by google or some shit like that.
I dont know to what extent it affects where your page comes up in the listing for a given search term. I imagine google keeps that info pretty well guarded, although there are probably websites devoted to figuring out google's algorithms for the shear sport of doing it.
PR matters mostly here because unless you have X amount of PR, a lot of link lists wont bother even looking at anything you submit to them. One of the reasons I think highly of Greenie (
LULZ) is because he doesnt seem to do that, and gives everyone a chance depending on the quality of free-sites they build and submit. That is rare in this business today. He isnt the only one, but he's one of the few big dogs that seems to not have forgotten who and what helped him get where he is today.
My advice regarding PR - build lots of your own domains and get lots of inbound links from free-site lists like GG and TGP galleries like PK. Link to your own sites, but dont overdo it.
I havent tried it yet because I've been too busy, but you might look around for link dumps and slow moving futabas that don't have "nofollow" in there page source and post a few links to your sites there. Also, hard link trades with other sites. Don't expect GG to give you a front page hardlink, but you can find other beginners with PR0-1 that will.
And dont fuck people by taking down their link after they put up yours. In general, dont fuck people at all.