http://atari-computermuseum.de/ states the 1976 release of the Atari 2600 and the apple I.
(the atari 400 and 800 are 1979)
According to:
http://www.gondolin.org.uk/hchof
the vic20 is 1981; the PET machines are older by a couple years, but are large bulky beasts.
The Sinclairs start in 1980.
The TI/99 is 1982 (and 16 bit!)
http://www.maxmon.com/history.htm
says the apple I was released in 1976.
The Apple II was released in 1977, as was the PET (by commodore)
http://www.tim-mann.org/trs80faq.html
TRS80 Mod1 1977
http://www.nickm.launch.net.au/ProjectArchive/index.html
The CoCo (RadioShack Color Computer) is 1983 or 1984.
To be brutally honest, the computers available in the early-to-mid 70's were large, hard to use, and not terribly powerful, even given the bit-depth and memory limits.
The Personal computing machines had few applications (the only one MWM said he'd seen was a switch-programmed one), and the terminals and workstations of the day were (given access space) 0.5Td or so.
The small machines referenced above all post date or parallel the development of the traveller game. The Atari 2600 predates the development cycle, as does the apple I, and the atari was at least beyond lack of notice; it was not, however, advertised for it's computing power.
Most of the sci-fi of the time likewise posited huge computers, or at least huge and impersonal interface panels. For example, in Star Wars, it is apparent that the interface for the computer is some chunk of the huge array of switches.
Likewise, while Star Trek was not active on TV, the ST Tech Manual showed us a central computer array of at least some 20 Td... and the 1977 ST:TMP (Officialy "The Motion Picture", unofficially the Motion-less picture) shows us a huge machine (1000km+) to have the intelligence of a sophont... (I wonder, did V'Ger encounter the Borg?)
Buck Rogers (TV series), a couple years later, shows a belief in the rapid shrinking of computers; Dr. THeophilus being about a liter for a superhuman intellect.
Had Star Wars (which triggered Traveller, according to MWM's article in Dragon), or Traveller, been a couple years later, the view of computers would probably have been MUCH different. But Neither Marc nor lored, by their own admissions, were computechnophiles before traveller began.
and CT, BTW, is 1977. As is Mayday.