Hi Jantje,
I'd like to point out that I downloaded the Eclipse Classic (Eclipse Indigo / 3.7.1 / eclipse-SDK-3.7.1-win32.zip) and added the C/C++ tools, and the plugin works great.
I believe that the only differences between that and "Eclipse IDE for C/C++ Developers" are the plugins that come with it. I think that you just need to install the ""C/C++ Development Tools" (CDT). I do have other plugins installed, so I may be wrong about that. But I know it's working, and that's the version of Eclipse I installed.

However, I am familiar with Eclipse and I'm a professional programmer who has written C/C++ for a long time. I do think your recommendation is best for general instructions. I just wanted to mention this for the more experienced people that may already have another version installed.
Since I said it works great, I have to say that I've found a couple of problems.

They're relatively minor, though.

The first is something you wouldn't normally do. Import an Arduino library; delete the folder it creates; then import the same library again. This breaks the build. It looks like it's including a relative path twice. E.g., import SPI twice and the path(s) in the project read "SPI/SPI". Import a 3rd time and you'll see "SPI/SPI/SPI".
The second is that projects created are not portable; either across platforms, or even across folders. By across folders I mean that if I rename a workspace folder, then open the workspace (in the renamed folder), I get errors that I didn't get before. This is something I hadn't tried with Eclipse before, and since the Arduino plugin does not create the workspace, I tend to think it is an Eclipse issue.
What I'd really like is to be able to commit a project file to GitHub and allow collaborators to 1) download and build the project and 2) modify the project and push the changes so that I could pull them down and build.
I've not looked into either issue. I plan to install Ubuntu on my Linux box this weekend and see what's involved. So I may be able to provide more details. (I do know that the project doesn't work as-is on Linux because a friend couldn't build unless he created another Arduino project and imported the files.)
Finally, you
should take the thanks seriously! IMO, This is a very important project. I do appreciate it, as I think others do, too.
Best regards,
Leland...