I wouldn't buy any domain based on Google
PR.
There is a scam going on right now where people are selling high ranking domain names (
PR 9 and 10)
but as soon as you buy it and google update it's records,
PR drops down to 0.
I've tried it myself and I really can boost Google's
PR to 10 in less then 2 weeks but it doesn't last ( it stays at 10 until Google's next update which is ususlly just a couple of weeks)