I don't really have a favorite op amp. There are so many good ones. Some audiophiles like to swap out op amps and talk about how good different ones sound, but I think that's a bunch of hogwash. If you believe that choosing the right op amp for an audio project has an impact on the sound, I'm the wrong person to ask about it.

There are some exceptions, like if you need a microphone preamp with 60 or 80 dB gain, but I have no experience in that area.

For audio, it's hard to go wrong with the OPA1654 for DIY projects that are not cost sensitive. It draws a lot of current. For battery power I'm intrigued by the TLC2264 which, while having somewhat more noise, has very low operating current and rail-to-rail performance.