thanks for this wonderful page. I’m thinking of installing ardour on my pc. Because I didn’t find any hints to my question, I wanna try it here. Sorry, if it’s maybe not welcome.
"Is it possible to import Cubase Files (SE, SX, etc.) [*.cpr} into ARDOUR? Is it possible to work within former Cubase Projects (including samples)?"
Simple, but important question.
Thanx to all,
fUNNy hEAd
cubase files cannot be read in ardour. All you can hope to do is export tracks into standard broadcast .wav files, and import those into a new ardour project. If you do it right it will preserve the relative time positions between different tracks. You would have to re-do all the rest, like slider automation.
The practise of using a proprietary file format deliberately to make it hard for people to move to a competing software product is known as "vendor lock-in".
There is a bit of software to automate exporting all tracks from a Cubase project…
However, it’s a bit of a hack as it works by running at the same time as cubase, taking a screen shot, and generating keyboard shortcut commands.
You also have to pay £20 for it, and it’s still a ‘dumb’ export so you need to flatten the mixer and turn off insert effects etc.
The joys of proprietary software. 
I normally just solo and export each track by hand, like Seb said.
I think there is a somewhat faster way by generating a small piece of audio before the start of each track, and doing bounce together/consolidate/conform (in pool) and save to new project. I can’t remember exactly what I did to get that working though, and definitely recommend working on a backup copy!
google for “proconvert” (formerly “cui bono”). eventually, this will support ardour too. audio only, though. no automation, no plugins etc.
There is a tutorial video on how to export all tracks in Cubase, but it’s only in german:
http://www.audio-workshop.de/download/aw_tutorial_1_stream.mov