Alteraeon is a good start, though bare in mind other muds aren't quite as well put together in the soundpack department, so don't get spoiled on the idea of muds always being audiogames.
Also, check the database since several muds have pages here, especially those with good screen reader adaptations.
For what muds to play, it depends what you want.
If your more into the hacknslash, aardwolf or Erion. Aardwolf is larger, but with harder quests and more eclectic areas, Erion is smaller scale but is over all more focused, plus it has great random systems.
If you want to get into crafting and rp and exploring, Clok is definitely worth a try, while if you fancy something focused around a scifi universe I'd personally recommend cosmic rage (which also has an amazing soundpack).
If you want to explore, do quests and learn about the world, Frandum is what I'd suggest.
With our dreaming and singing, Ceaseless and sorrowless we! The glory about us clinging Of the glorious futures we see,
Our souls with high music ringing; O men! It must ever be
That we dwell in our dreaming and singing, A little apart from ye. (Arthur O'Shaughnessy 1873.)