How to say "in my opinion" in chinese? For example, "In my opinion, this music is very good".

The translation indicated by Google, 在我看来, seems rather dodgy to me.
我认为，我觉得，依我看，在我看来，依我之见，etc.
In your condition both are okay. But in daily life I would say 我觉得 since it's more common and informal.
窃以为 is an ancient-feel formal word for that , so is 恕我愚见.