I'm really impressed with the prices of Bridgestone bikes. Some models like the XO line, RB-1 and MB-1 command some serious buckage and are highly desirable.
Which bike brands/models that sell now would keep their values or even go up 10-20 years from now.
For me, I think if Surly were to somehow disappear now or in the near future, their bikes would experience the same sort of status. They have an unique brand image and their bikes are well thought out.