Speex isn't a hack, it's a sound format made specifically for speech. The builtin music player does not currently play speex files.
For getting comparable music in ogg as you would in mp3, take the mp3 bitrate you would normally listen to (128, 160, 256, etc.), cut it in half, and add 5-10kbps. It will probably sound the same, if not better. If you listen to 128kbps mp3s, 64-80kbps (q0 - q1) will sound fine to you.