I still remember playing Jazz Jackrabbit with the controller that you plugged into the computer, and was amazed how it was like my nintendo.
Duke Nukem was amazing as well, then Duke Nukem 3d came out with the strippers who turned into aliens if you shot them... then piece of shit Duke Nukem came out for xbox that I had to buy just because of all the fond memories...
First game I remember beating though was Sid Meirs Civilization...who needs science when you got big ass guns.