1981 1 GB IBM hard drive model 3380. Starting from $81,000 and weighed in at 34 kg.
versus
2007 1 GB smart card. Starting at $9 and weighing in at a...well a uh...a few grams maybe?
Eh...if this isn't the most striking example of the law of accelerating returns I don't know what is.
More info:
http://www-03.ibm.com/ibm/history/exhibits/storage/storage_3380.html
http://en.wikipedia.org/wiki/IBM_3380#IBM_3380
http://commons.wikimedia.org/wiki/Image:IBM3380DiskDriveModule.agr.jpg
Hat tip: http://sd4.sd-lj.si/diggit/20yago.jpg