Meshuggah, been leading the way in metal for 30 years.
I don't often meet people who have even heard of Meshuggah. They would certainly keep it interesting musically but wonder whether it's almost too heavy to sustain for an extended period of time. Demiurge is such a tune. I is a 21-minute masterpiece.
I by Meshuggah
Mine would probably have to be the Aghan Whigs - plenty of albums and varied enough to keep it interesting.