Late to the Miata world, I purchased my 1995 Brilliant Black in August of 1998 with 32,000 miles on the odometer. I had wanted one for years, finally found the perfect one.
The odometer turned 100K on the IMS track. Having carefully planned this event, the odometer turned over to 100,000 as I crossed the famed yard of bricks in May of 2006 and I've got a picture to prove it! My personal 100K miles driven in the car came in 2008. Not sure where I was, I do remember looking down and thinking, "I've driven 100K in my Miata!"
My car and I have been to New England, Canada, east into the Appalachian Mountains, (Why, what's that semi doing on Tail of the Dragon?), Colorado and the Rockies, all over the midwest. I did slow down a bit putting miles on the car and when the car and I parted ways, she had 185K+ miles on her. I loved that car...
I really do think that owning and driving a Miata is the most fun you can have with your clothes on.