In 1986, you could bring up a network of half a dozen Sun workstations, each running a perfectly capable 4.3bsd-derived Unix which most people today would be perfectly happy to use in terms of functionality (the 15MHz 68020 might not be such fun) off a single 327MByte Fujitsu Super Eagle disk [1], with plenty of room left to do real work.
Today, the installation image for a Raspberry Pi is 1.8GBytes.ians-macbook-air:Downloads igb$ ls -lh 2012-12-16-wheezy-raspbian.img
-rw-r--r--@ 1 igb staff 1.8G 16 Dec 18:52 2012-12-16-wheezy-raspbian.img
ians-macbook-air:Downloads igb$ And the update kit looks like about another 475MBytes, too. remote: Counting objects: 21472, done.
remote: Compressing objects: 100% (7381/7381), done.
Receiving objects: 70% (14868/21219), 331.89 MiB | 32 KiB/s
[1] I found the securing straps from the pallet it was delivered on recently: I'd been using them to tue things down in the boot of one of the cars.