While I am not his greatest fan...there is a fellow, Eric Kunze who
probably is.  His Hovhaness discography of 1997 is some 76 pages!  While
I am not anywhere near as complete as Eric...I think I have recordings of
about 42 of the Symphonies.  The highest number I have in recording is 67.

As for recommendations: I can only say that my favorites are

1,2,3,15.16,50 and 58.

I should add that many of the recordings I have are of non-professional
orchestras and often the sound is lousy.

While I find that he repeated himself...I also feel that way about
Haydn...some of the works have distinct personalities.  I find the
contrast between the 15th and 16th to be remarkable.

He also wrote a substantial amount of chamber music that is quite
attractive.

Karl