Hi Glenn,
Welcome to the forum and to Band-in-a-Box. There are two midi sounds you may want to consider. First is the TTS-1 virtual sound module from Cakewalk by BandLab and second is the Timbres Of Heaven virtual instruments. Both have the advantages of sounding good and are available for free.
The TTS-1 is 100percent general midi compatible so whatever midi instrument Band-in-a-Box selects the sound module will playback. The sound module can playback up to 16 instruments at the same time. The instruments sound about as good, or a little better, than the Coyote Forte instruments. TTS-1 was one of the sound modules used in the PG Music comparison.
+++ HERE +++ is a recommendation from PG Music's leader, Peter Gannon. The downsides are only the 64 bit TTS-1 is available and you must install the free Windows DAW, Cakewalk by BandLab. Another plus is you also receive the Studio Instruments VST suite of strings, electric piano, electric bass and drums.
+++ Timbres Of Heaven +++ is a gm compatible Soundfont. The Soundfont is a large (about 256 MB) set of instrument patches that can be loaded and played in any Soundfont sound module including Sforzando and Synthfont. The Soundfont was developed by Don Allen to provide high quality playback of midi Karaoke and gaming files.