Here's a round-up of some of the SoCal libraries:
LA Public Library
epub: 3,127
pdf: 2,918
mobi:243
audiobooks: 6,364
County of LA Public Library
epub: 946
pdf: 289
mobi: 0
audiobooks: 2,704
San Diego County Public Library
epub: 676
pdf: 63
mobi: 0
audiobooks: 1,192
San Diego Public Library
epub: 481
pdf: 0
mobi: 0
audiobooks: 2,356
Orange County Public Library System
epub: 200
pdf: 0
mobi: 0
audiobooks: 3,496
Pasadena/Glendale Digital Library
epub: 42
pdf: 1,192
mobi: 0
audiobooks: 903
LAPL and CoLA pretty much have 95% of what I read - stuff that's on NYT bestseller lists. Both libraries are also active in reading purchase suggestions, and typically add books 1-2 weeks after I suggest them. Thanks to them, I haven't bought a book in months, and the waiting lists are still fairly reasonable.