I would recommend the 1st violin sonata released by PAVANE, please check out Disc No. 18 in the Discography section of my website:
http://www.joseph-marx.org/en/discography.html#ChamberThe remaining chamber music (all piano quartets, a huge piano trio and the 2nd violin sonata) plus the unpublished solo piano and organ works will be recorded as a world premiere by cpo in 2009, also the quite rarely performed songs for medium voice. I also recommend the solo piano CD that was released by Chandos, performed by Tonya Lemoh.
As I wrote yesterday regarding the orchestral works, some expert listeners say that parts of the ASV series may not be referred to as reference recordings; this might indeed partially be true for Vol. 1 (Nature Trilogy), Vol. 2 (even though this Orchestral Songs disc received a GRAMMY nomination) and Vol. 4 (the Piano Concertos). Incidentally, my own role in the planning and production of the ASV series which was much more extensive than just writing the liner notes is described to some extent in the Recording Projects section of my Marx website). Therefore, the Joseph Marx Society is working on alternative recordings which will hopefully present the composer in a more perfect light.
I also suggested the almost cinematographique Nordland-Rhapsodie to cpo. Mr. Schmilgun is strongly interested in making Marx's not-yet-recorded works available as soon as possible. And finally, as mentioned previously, there are a couple of major conductors who apparently would like to perform or record the Herbstsymphonie.
But for the moment, I would strongly recommend the forthcoming Chandos release of Marx's choral works and orchestral songs (CHAN 10505). On this disc, you'll find not only the magnificent cantata "Herbstchor an Pan" (Autumn Chorus to Pan) as a premiere recording, but also first recordings of some choral works that were orchestrated (i.e. arranged for mixed choir and orchestra) by myself and the Vice President of the Marx Society, Stefan Esser. The sound world of Herbstchor an Pan and the orchestral songs will be most appealing to many listeners but we still hope that our orchestral versions of the other choral works (including "Ein Neujahrshymnus") will also find a few friends out there.