Why didn't I see this thread before?
OPL-3 actually has a LOT more than just mere "farting" noises, it has one of the best drum sets in my opinion (especially those hi-hats and crashes, I almost can hear a triangle wave in the hi-hats, love it). Good bass as far as FM synthesis goes.
I'm now using my AWE64 for most of my DOS games, GREAT compatibility with all of them I should add: but I have it still routed so I can use my lovely Crystal FM Synthesis (a modified version of OPL-3, I think it's better actually, you can see one of the commenters in the video above theorize this).
Also, Bobby Prince composed a lot of his tunes specifically for FM synthesis. I find running certain midis with things like AWE64 to sound weird. It's also worth mentioning that a lot of DOS games used a special form of MIDI card detection: so it would change the instruments based on what would sound better for that particular card.
This is why when you get midis from
http://mirsoft.info, they often sound different in-game: I've experienced this with the Hexen I midis. They sound AWESOME in OPL3 I should add.
Here's an example of a modern rendition of a hexen track:
If you listen right at 1 minute in the music, you'll notice the supporting grungy bass is lacking... whereas in OPL3 you'd hear it mix well with the horns.
I should actually record and upload a proper version of that song later to youtube... Kevin Shilder composed those of course.
Typically though, if you want the best sounds for midi files, I'd suggest a JV-1080. That thing can make midis sound awesome. You just hit "shift" then "perform", and it'll perform general midi. However, a certain phenomenon I noticed is that the JV keeps old parameters from different midi files, it doesn't refresh (meaning there can sometimes be excess reverb, or no reverb when there SHOULD be)... so... you either have to refresh it by powering it on again, or reset performance mode.
EDIT: forgot to add, Roland is my favourite for music stuff too.