Mortal Kombat - I met my mate from school down the seafront on a couple of occasions during the school holidays just to go and play this one game. I remember going to Woolworths with a bit of paper and writing down the fatalities that were printed in CVG before I met him.
We probably pumped a fiver in each, then I remember going to the chippy for lunch and then going back to the arcade and spending whatever we had left to try and thrash Goro. When Mortal Kombat II came out we did the same, except this time my mate knew how to drop a certain gambler and we would go and do that when we ran out of money lol. Good times.
WWF Wrestlefest - There was a sit down version of this at one arcade I frequented. To this day it is one of my favorite arcade games and I still play it regularly. You would really get your money worth as the matches lasted ages and the first couple of levels were easy. I got to the last level to fight Legion of Doom many times but never won in the arcade. I've since completed it on my home machine after reading some guides. Very interesting game and just beautiful to say it came out in 1991.
In later years at Uni, honorable mentions go to Sega Rally, Time Crisis, House of the dead and Tekken3