Back in the day I remember playing a demo for the Desperados game, and it had the most insanely long loading time. It felt like waiting 10 minutes for it to load, but it was worth it.

But looking back, I can't help to wonder if my subjective feeling at that time was wrong by a long shot. I never timed the loading screen, and other games at that time I compared against weren't loading snails even on that old hardware.
I'd wager that I've witnessed longer loading screens from modern games than I ever did from that old demo.