The Control Data Corporation 160 Computer
The CDC 160 computer, introduced in 1960 was the first truly small computer to hit the market. This machine and the DEC PDP-1 may both fairly claim to be the first transistorized computers to come to market, but the DEC machine was hardly small; A PDP-1 filled approximately 3 EIA standard 19 inch relay racks, while the CDC-160 was packaged to look like a standard double-pedestal office desk.
The CDC 160 was sufficiently successful that CDC followed with the 160A and the 8092. The base configuration for a CDC 160A cost $110,000 (as remembered by George R. Gonzalez); this gave you the CPU, minimal memory, high-speed paper-tape reader, medium speed punch, and a flexowriter. An assembler and a 4K FORTRAN compiler were available, but not much else.
Photos of some of these machines are available.
While the CDC-160 computer is not widely studied, it was one of the most important predecessors of the DEC PDP-8 computer, and the latter is generally recognized as the most important small computer of the 1960's.
A modern manual (under construction):
A Programmer's Reference Manual for the CDC-160
From Gordon Bell's talk on Cray's computers
From George Michael's history of computing at Livermore