I've got around 50 verified incoming links to my site and I jumped from a Google PR of 0 (actually gray) to PR of 5. Yeah! Now, I'm unsure what to do next. Should I continue to exchange links with as many relevant sites as I can find, or only those relevant sites with PRs of 5 or higher. Thanks.
Do not ingnore any chance of exchange valuable links with other sites! Quality links(PR>5 at present) would bring higher page rank to your site. A quantity of links would lead extra visitors to your site.