I agree with Simmo! but would like to add another factor.
Site A may have 1000 inbound links but have an equal amount of outbound links.
Site B may have only 100 inbound links but 10 outbound links.
In this scenario I would say that Site B links would have more weight. I view page/site strength as water and links as canals. You only have so much water (strength) to distribute and the more canals (links) you have, the less water each canal carries.
Another factor is where is the link placed on the site. Is it on the strongest page of the site that has all the inbound links, or on some sub page with only one link to it from the strongest page?
Just some thoughts on the matter
-Philipseo