ZeroRadiant (aka. GtkRadiant) 1.6 is in development. We've seen some recent developments. If you would like to try the latest binaries and help with the development and debugging process, this thread is for you.
The official GtkRadiant SVN contains the basic 1.6.1 binaries. Be aware that while the SVN is updated, there hasn't been new binaries compiled since Sept. 2008. That said, you'll still need the binaries to get started, so make sure you download that zip.
xpc (aka. mfn) has been working on an experimental branch of 1.6 that is helping to progress the development of ZeroRadiant. Grab the latest binaries and change log and report bugs on the mfn/GtkRadiant gitHub Issue Tracker. Add discussions to this thread.
-Obsidian
Updated: Jan. 20, 2010
Been out of it for a while, so I was wondering what the state of GTKradiant 1.5 is in. Last time I checked support for Doom 3 dynamic lights was being added.
The folks using 1.5: What things have been added that you would not want to miss, or that you really appreciate compared to the good old version 1.2.13.
Anything new happened with q3map2?
Presently thinking of continuing work on aeglow, looking into what I should download an update to be "with it" again

Thanx.
Edit: Just checked GtkRadiant-1.5.0-2005-01-16.msi indeed seems to be the last release. Snief. And of q3map2 I had version 2.5.15, and the latest stable release seems to be 2.5.16.