1950s - Roll Over Beethoven
1960s - sympathy for the devil
1970s - london calling (although it came out at the tail end of the decade)
1980s - Burning For You
1990s - Plush
2000s - not sure
disclaimer: done off the top of my head.
Nostalgia mostly. People tend to like the decade they grew up in and all good music grows on you with time. Undoubtedly in 5-10 years there will be some songs from the early 2000's you love to hear.