I agree with you both! (ctabuk & mjtaylor)
The main focus when searching for a site to try to get a link from is the relevance of the site... I wish more people would focus on the fact that this is Marketing and not just Search Marketing. Links from a relevant page will give you direct traffic! And they will help your Search ranking tremendously!
However if you have a page that's not on topic (even partially) then taking a peek at it's
PR (even though it may be out of date) can help you to determine if it's a good link or not.
Crunching the numbers though, always go for a relevant link rather than one with a high
PR. Find one with both and you'll have no worries.