Hard to say
The damn things are so bloody amazing these days, games from ten years ago have no chance against the new titles.
Having said that, I'll nominate...
NHL 94, 95, 96 - Sega Genesis
The very version seen in the classic scene from Swingers . I too used the Blackhawks and Roenick was a fucking badass.
Rambo - Sega Master System
Crap by today's standards, but at the time, I spent every free moment trying to finish it. And when I did, boy was it a treat. I must have gone through 3 or 4 controllers playing it.
Winning Eleven 7 (and the upcoming 8, 9 , 10 etc.)
Finally a football game for those who appreciate gameplay and realism over graphics and official liscences(EA). I play it every day.