well in case of google PR always helps. But PR is not everything. content and keywords, and backlinks also veryimportant
No it's nt just about good PR. it is also about good on page search engine optimisation which basically means that you have the following meta tags title, keywords, description all unique to that particular page. It's also about building back links to your site from do follow blogs, forums and link exchanges with sites in a similar niche to your own. It takes time and effort but is well worth it.