Ahaaa. The familiar post about Google PR. To be honest, it all depends on who the buyer of the domain is. PR might not mean as much to some as it does for others. However, the nature of having good Google PR in general would mean that the site has quite a few quality back links and lots of content. That alone in my opinion increases the value of any website. But, I would never buy a site myself based on just PR alone. The buyer would still need to like the domain name itself. A site could have great PR and lots of content, but the domain could be worthless to someone who does not feel the name relates to what they intend on using it for.
I hope that helped.