Greetings,
I have been working with video editing/compositing for a while now, and have been using a combination of open source and proprietary software. I would like to switch to all open source, but I don't quite know where to start. I have done quite a bit with blender (mostly green screen), but I haven't used its video editor much. I am familiar with iMovie (don't really care for it, but it came free with a mac), but would like something better. And of course Audacity. I am wondering if I should try to learn blenders video editor, or if there is an open source alternative to something like Pro show producer. Any suggestions are welcome.

Thanks in advance.

you should definitely look into the video functions of blender. Though the editor is pretty simple, you have the possibility to stuff your videos into the render pipeline - along with the node compositor and your 3d scenes - which is very cool.
If you plan to do all your video work in linux, you won't be set with one software anyway. The most advanced nle for linux is cinelerra but it has its glitches and the timeline is fiddly to use. For the not-so-advanced stuff there's also openshot, kdenlive, pitivi and several more.
If you don't mind booting to windows to get a better result, take a look at lightworks. This is a really professional software, that has gone open source.

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Hmm, I don't have windows ( I "cleansed" my system a few months back ), but lightworks may run in wine. Has anyone else had good/bad experiences with any of the above mentioned software, or have a favorite?

You might take a look at SlackerMedia. The site was conceived with Slackware in mind, but most of the information should transfer to other distros.

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Being a Slackware user, I will definitely have a hard look at that. Of course more opinions are always welcome.

Not sure if this is what you are looking for but the alternative to vegas pro (windows ap) is kdenlive. It is simular but not sure how to use it yet.

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Here is a Ubuntu distro, specifically tailored for the a/v enthusiast in mind.

http://ubuntustudio.org/

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