The other day I was comparing different Smalltalks with a friend to see 
how many classes it takes to have a certain amount of funcionality. For 
example, Little Smalltalk 4 has only 54 classes while Self 4.1.6 has 
917 parent objects (more equivalent to traits than to classes).

So I took a look at the Squeaks I happened to have on my machine  (using 
"Metaclass allInstances size"):

Squeak 1.16: 355 (adds color, sound and vm implementation to Apple 
Smalltalk-80)
Squeak 1.18: 305 (HyperSqueak eliminated)
Squeak 1.19b: won't run (Morphic and sockets added)
Squeak 1.2: won't run
Squeak 1.21: 390
Squeak 1.22: 398
Squeak 1.23: 403
Squeak 1.3: 482 (jitter, links in source, more music, more morph and a 
wikiwiki server)
Squeak 1.31: 496 (bug fixes)
Squeak 2.0: 512 (pluggable views, auto updates, MIDI)
Squeak 2.2: 668 (email and other stuff)
Squeak 2.3: 782 (vector graphics, web browser)
Squeak 2.5: 1006 (IRC, eToys, 3D+Alice)
Squeak 2.6: 1089 (plugins)
Squeak 2.7: 1170 (speech, several goodies)
Squeak 3.0: 1546 (morphic now default UI, Nebraska)
Squeak 3.1: 1811 (handwriting recognition, StarSqueak, MPEG player)

-- Jecel