By the time Madden NFL 95 came out, the series was already six years old. But Madden NFL 95 took the series from great to outstanding.
We finally had NFLPA rosters, no passing windows, realistic weather conditions, lifelike player animations, in-game stats, a TV-style presentation, variable injuries and more.
Since 1998, the series has sold over 90 million copies, but it was Madden NFL 95 when the series broke the final tackle and sprinted uncontested* toward the endzone.
*Yes, I remember the NFL 2K series. It was a great series that almost pushed the Madden series out of bounds as it was running toward the endzone (or whatever other analogy makes sense).