That a very astute observation, Libby. According to the AFL-CIO blog:
Easily forgotten is how close 15 of the Republicans’ victories were in 1994. Had Democrats in key districts won a combined 52,000 more votes, there would have been no “Speaker Gingrich.”
Don't ever think your vote isn't important. As the post above says, it's likely there will be many close races this November too, and "the outcome of these races will determine the political environment for the 2008 presidential election and years to come."