Roy Osherove is asking about Smalltalk in the enterprise. Gemstone Smalltalk was the first object-oriented application server to my knowledge. The core architecture has been in development for about 20 years. The systems developed include manufacturing floor, billing, banking, insurance, shipping, and logistics applications.
There are a surprising number of new web applications running Gemstone Smalltalk too. I would probably choose Cincom's VisualWorks over Gemstone today since it now has a lot of server capabilities, better web tools and objects, as well as better product support.