I think for a modern bike to be collectable in the future, it would have to capture the zeitgeist of bicycling in it's time. It would have to be devoid of any elegance, symmetry or understatement. It should be a cacophony of awkward, unbalanced lines in garish colors. Every possible surface should scream something at you. You should never be left wondering what company made the components. It should be something that brings future onlookers back to the early 21st century no matter how much it assaults their senses.