The rules: each of the last eight decades—including the one in progress—must be represented. No one decade can be represented more than twice. Collections may contain vsf but not novellas. Collections may not be retrospective (i.e. no 'Selected' or 'Collected' stories). You have twelve picks.
I made up those rules. One of my great pleasures in life: following rules of my own making.
What's on yr list of twelve? My list of twelve goes up soon @ Ravi Mangla's new site, Recommended Reading.