In regards to nezplug, there is an "unofficial" version that is still updated by another person that goes by the name nezplug++.
http://offgao.no-ip.org/program/nezplug++.htmlThe thing about nezplug++ is that with every update, it seems to improve one systems emulation and screw up anothers. Overall though it's definately making the most progress for several of the chiptunes it plays. Check out various old versions, most updates are spot on for ~90% of the hes files I'd say.
Correct me if I'm wrong, but .hes files work just fine in any pce emu that flat out didn't suck, ie any that could load at least one commercial game. Button I and II would change "tracks" by jumping to addresses in the rom. I haven't gone that route often, but just renaming the extension from .hes to .pce was usually enough to get them working.
If you are going the emulator route, it's only worth it for the few hes files that are broken in all the .hes music players, otherwise setting up some hardware to capture the audio straight from the hardware is about the same amount of hassle.
I only went this route for games that use ADPCM, and the few that just plain didn't work for the longest in any plugin based player, or if they did, they were constantly being broken after a short update of being fixed. Final Lap Twin is one that comes to mind. After nezplug++ implemented ADPCM I have never messed with emulators to play .hes files since.
Speaking of Final Lap Twin, I still hum the one tune that plays during the practice tracks (iirc) in the rpg mode sometimes when I am driving. :oops:
Xanadu I and II have some of the best tracks period, and so many overall. Granted they don't represent some of the other feels and styles of many other excellent games' tracks, but Xanadu I had maybe 2 total redbook audio tracks and something like 60 EXCELLENT all around psg tracks. Xanadu II had less psg tracks, but still same top notch quality that falcom is known for.
I also recommend Bloody wolf, if it hasn't already been mentioned, it has some great action packed music fitting to the game overall. It also has a bit of variety in the music, and while I don't like some of the tracks as well, I think they fit their respective stages overall. The jungle stage's music is one that comes to mind. They also made good use of stereo, but only on the title screen. Blew me away as a kid, that and the game plays the sound something like 80% louder than any other I can remember.
The one dungeon explorer and a lot of others used sound very similar, you could even take the music from a lot and shuffle them around and no one would notice. Also Neutopia I and II and a ton of others (majority of hucards period) seem to be using the standard dev kit engine for sound, not that a lot didn't sound great. Definately a top 10 will be hard to narrow down, but for sure it needs to represent all the different kinds of awesome on the pce.
A lot on this list are certainly tastes of smaller groups, and if you took ParanoiaDragon's suggestion for Impossimole, I do believe you'd have a mob of angry pce/tg 16 fans show up to your door. Just run by your list before you set on it, if there's any dissention, believe me you'll know if something doesn't belong.