I'm wondering how much a link from a related site is worth as opposed to an unrelated site. If they are both PR 4 for example, how much more valuable is the link from a site with similar content?
It matters less than people think. You will read endless threads and posts from people saying that Google will come to your house and shoot you if it finds a non-relevant link, its simply not true. A quick scan through a site with good SERP's in yahoo explorer will show you that most sites have dozens of unrelated links to them. You cant control (mostly) if people want to link to you, and it would go against many principles of the net if only relevant links counted for anything. So relevance is a factor, but don't fall for the nonsense spread around forums and pass up a good quality, non-relevant link opportunity.
I'll 2nd what thefandango says, but don't underestimate the power of a good PR link from a contextually relevant page. A good mix of both will work wonders.
Thanks for the input. I'm just wondering because I'm struggling to find sites in my niche either willing to link or just no longer updating their sites. I didn't want to attempt to get links from unrelated sites if it wasn't going to be very worthwhile and in some cases hurt.