You need to look beyond the PR linking-back game and explore how your web destination brings "added value" to the online world.
If you're providing your visitors with a truly UNIQUE and USEFUL web venue, then the links will start popping up without you having to ask for them.
It'll mean working like crazy to create such a complete, professional and compelling web destination but those are the web sites that outperform all the "link-farm-a-holic" web-spam-pollution out there.
Work hard, be unique, serve others.