In-ear earbuds are basically earplugs, without the social stigma; of course, you may feel like a bit of a tool for wearing headphones to avoid the shame of earplugs.

Classical or instrumental music might be also worth a try if you haven't tried it already; post-rock works well for me.

As for phasing it out, unfortunately conversation is much harder to tune out than thing like engine noise. Our brains are designed to pay attention to talking, and the intensity and tone are constantly changing.