A buddy of mine was ruining parties with Obituary's cause of death when he was a teenager - LOL

Keanu Reeves as Shadow the edgehog. lol [link]

This is also good for starters [link]

I show them Torsofuck.

There's also Prong with albums like Rude Awakening that's not to aggressive and catchy.

Rammstein is good because their not always heavy and they have a bit of variety and a bit different from your standard metal sound

When introducing friends to metal, my approach is to choose the most prolific musicians among my favorites, like Devin Townsend or Dan Swanö and then play their most accessible projects/albums. It has worked well.