How was the 1992 presidential election different from other recent elections?
The biggest difference between the 1992 presidential election and the ones in 1996, 2000, 2004, and 2008 is that in 92 there was a viable third candidate for office, Mr. H. Ross Perot. It's not just that he existed (every election has a slew of candidates from minor parties,) it's the fact that he was polling high enough to allow him a spot in the televised debates.
In order to be invited to the debates (which are, ironically, run by the two major parties in the US through a commission,) a third party candidate must be getting at least 15% of the vote in 5 public opinion polls to be considered "viable." This number virtually ensures no-one but the candidates from the Republican and Democratic parties will have enough support to participate. In 1992, though, Mr. Perot's level of support averaged higher than that, earning him a spot.
That's the biggest difference. If your question was just taking a look at this year's election we could also talk about "SuperPAC" money, but because this is such a recent change it doesn't really relate to the extended nature of the question.