You can argue cost or circulation figures with me all day... I love bookmobiles. The late Allen Smith, farrier and inspirational tutor at Simmons College (library school) once said if he had to do it all again he'd rig up an RV as a bookmobile with satellite internet and organize stops at the houses and farms in the area he served, instead of financing the library. He was only half joking. Found the mother of all bookmobile photostreams as above on flickr. Thanks to ExileBibliophile.
(Bonus mud season shot below, via Sybil McShane's Mobile Library Literacy: Solutions for a Rural Environment)