wheel - 4:59 pm on Jun 25, 2008 (gmt 0)

None of those. I want links to boost my rankings. Which to me is not the same as PR.

And as P1R mentions, I do it so that my rankings are there for the longterm.

And that means that I have to build quality links that will withstand future algo changes. I sometimes will go after links that probably don't mean much right now, but I expect will in the future. Four things I look at:
-relevance of the site giving me a link
- trust of the site, basically determined by gut feel looking at backlinks to the site
- relevance of backlinks to the site giving me a link
-age of the site/age of backlinks to that site.

The age thing I look at right now because I think it matters right now, but long term I'm not certain it will be so important. Really the first three factors mean it's an old site anyway.