Although there are a few original and surprising inclusions, for the most part I suspect these professors are just showing off with their choices. The most honest answer comes from Nobel laureate Sheldon Glashow, who submitted a wonderfully crotchety response ("Was Moby Dick more important to me than the latest Len Deighton thriller, or is browsing through the Oxford English Dictionary even more significant? And who should care?"). Helen Vendler says basically the same thing, but in a gentler way.
Still, worthwhile for a quick browse. I learned about a few interesting titles.