(re: Building a Sierra Computer) Roland MT-64 is also a good middle ground, but is very rare. Saw one only at RadioShack, and I bought it, about ten years ago.
DX4s are good, but I’ve encountered some bugs that the first Pentiums had. However, the bugs are Windows 95 related (from my testing) and shouldn’t affect any DOS programs.
Getting both Rolands is possible, as RadioShack has a splitter for MIDI keyboards, it ought to work with MIDI mods for old PCs. Once you hear Roland (espcially on Mortal Kombat), you don’t want to go back.
A SoundBlaster16 is nice for stereo sounds, but older SB cards do more clear speech. The reality for old Sierra games is I’ve never heard Stereo effects on any, so I’d use an older SB card. Some SB cards allow the Rolands to go through the joystick port, or even some joystick cards from the past (like Kraft’s) would fool the Rolands into working, but this’s just experimentation and ought to be done only at one’s own risk.