high quality page rank is better than normal backlink. some high quality backlink is better than huge normal backlink.
you should check out your competitors website and see how many links they have and then have about 20% more links then them
As many as you can possibly get. But backlinks on relevant sites with a high PR is much better than 1 million backlinks on websites that have a PR of 0.
It's better to have quality links (themed content links), rather than having a number of links from spam sites and link farm.
most of us here suggested to get quality backlinks rather than normal backlinks...i agreed...when you are referred / linked from quality backlink (good pagerank website), google presumes that your site is good and give values to google...to me i am concentrating build quality backlinks...