You better concentrate into SERPs and marketing then into PageRank It's no use to have an PR9 blank domain name... or without sale able product on them ... + Who looks at a website pagerank!? Only some webmasters do. I think i will create an PHP script to track all visits from my signatures to see how many webmasters are using google tollbar ...
Most of the answers above are right. However I have seen sites with a pr of 3 in the top 10 for top keyword searches, surrounded by sites with pr 4 and up.When checking the links I noticed that the few links pointing to the site where totally relavant and there was always a link from either dmoz directory or yahoo directory. Its just an observation that might help you with your question. I could be way off with my answer.