High-quality open source NLE's may become a reality in the not-too-distant future. (If you're unfamiliar with the Open Source software, check out this article.)Lightworks is currently in beta mode and available for download. This NLE touts an impressive list of features. I'm testing this software now and look forward to sharing that experience here soon.
Novacut is now fundraising to help underwrite the release of its beta version. Here's an article from Studio Daily that describes the features to be included in this application.
If you want to support the project, check out the Kickstarter campaign here.