Horizon Variations by crowswing is an impressive crossover with Sandman.
I Hear My Neighbors Talking by orangesparks is a brief character study of the younger of the two Bernies.
The Replacements by muzivitch is a VeidtOwl fic in which Dan's name is never mentioned -- pretty impressive.
Solidarity by anactoria is a dystopian slashfic that is good even if you don't like dystopias or slash. Or Watchmen. Or fluffy bunnies. Seriously, this fic is really good.