Exactly 5 years later...
I'd say the most historically exciting 5 years was 1993 to 1998. You have the heyday of the 16-bit era, to the launch and failure of the next-generation pretenders (3DO, Jaguar, etc), to the launch of the real next-generation consoles (PSX, N64, Saturn), to the heyday of the 32/64-bit era with CD/3D based gaming and games that were so much deeper and more complex.
There was also a change in leadership of the console market 3 times, Sega being in the lead at the beginning with the Genesis, Nintendo taking over with the SNES' resurgence in 1994 and the early lead of the N64, and Sony taking over about late 1997. Sega left the console market temporarily at the end of this period.
You begin to see video games expand from their core market of young males to a more diversified audience.
As for the most changeful period in video game history, it might be 1982 to 1987 with the video game crash and resurgence led by Nintendo. But the technology change of '93-98 was a bigger leap, and from 1982-1987 not a whole lot of all-time classic games came out; '82 and '87 each were great years for gaming but the middle years, '83-86, weren't as rich with games in general as '80-82 or '87-on due to the video game crash. 1982-1987 had a couple of very exciting years on the fringes, but '84-85 were dead, dead, dead. I give it to '93-98 for that very reason; it was exciting the whole way through.
Obviously 1986 was an extremely important year as this was the year that the video game market was revived with the launch of the NES and to a lesser extent the Sega Master System and Atari 7800, and Super Mario Bros. was extremely important, but the NES-era games from 1986-mid 1987 don't have as many classics as, say, late 1987-1991. '93-98 had numerous great games being released throughout the period.
(Specifically, I'd make it Sept. 2, 1993 - Sept. 2, 1998, that way I get the launch of Mortal Kombat on home consoles in there)