Roger Weber over at Baseball Almanac ranks the greatest teams ever.

Including all teams? 1920 and later? 1927 Yankees. 1947 and later? 1961 and later? 1998 Yankees. The 1920 and later list has the Yankees in 8 out of 10 spots while the 1961 and later list (the list with the fewest Yankee entries) has them in 2 slots.

Via Steve.