These days I'm usually too gear-saturated (and besides, I already know which gear I want to get next), to just look at pictures of preamps and mics and whatnot....plus I already see all that gear on the Internet.
Though back in the day when I was just getting my studio together, I loved staring at gear catalogs.
If I take anything into the "library"...it's the audio trade magazines (which happen to be full of audio gear ads/reviews anyway), and maybe I'll read a music/audio article/interview...until it's time to wipe.