I've been in and out of the arcade scene for a better part of my youth, thanks in part to the men in my life back then. (Dad, my older brother, and my uncle.)
Space Harrier - Probably my single most favorite arcade game of all time. The sit-down was nice, but even if it wasn't, I would always manage to play the game at every arcade I'd visit. I got good enough that I could finish the entire game in two credits with a three life allotment.
After Burner II - Another sit-down I've always dreamed of owning. I've often wondered if it was possible to build a cabinet that does a full 360 when you did a barrel roll? Would still love to play Climax someday.
Double Dragon - Probably one of the most easily accessible games for me to get to, since it was located on my way home from school every day. I certainly enjoyed the first more than the second; the second drove me crazy with its insane difficulty, interchangeable attack buttons, and bouts of slowdown.
Spy Hunter - Dad was more into this I was, but I always enjoyed watching. Can't top that Peter Gunn theme, either.
Contra, Super Contra - The holy grails of run 'n gun shoot 'em ups, though honestly, I've had very little experience with the arcade versions back in the day. For whatever reason, nearly every Contra machine I've come across always had some defect; either the joystick wouldn't stay diagonal, or the fire or jump buttons simply didn't work. It wasn't until during my stint as a casual in the post office - where they had both machines in the GMF swing rooms - was I able to get ample time in with the games. Still think the NES versions are vastly superior anyways.
Pole Position, Out-Run - I've never been a big arcade racing fan, but these got their fair share of play time.
The Simpsons, Teenage Mutant Ninja Turtles, Turtles In Time - Nothing beats this trio of quadruple player beat-em-up fun. Often times when we attended bowling alleys or skating rinks, I would always attempt to stay away from the main activities to play these games. And I've often wondered why Santa couldn't bring me the number one thing on my Christmas list: a full-sized arcade of the first TMNT. My parents rationalized that the machine would be too big to fit on the sleigh, and that it couldn't possibly fit down the chimney. My response to the latter was that I'd leave the cellar door open for him to get through.
NBA Jam - Probably one of the few sports games I ever took to playing seriously. Tomahawk slam!
Terminator 2 Judgment Day - One of the few gun shooters I ever got heavily into, aside from Point Blank and a little bit of that Aerosmith-themed Revolution X. L.A. Machine Guns is pretty cool, too - I really dig the recoil on those guns, but you really need two hands to control one of those massive things. I got it in my head one time to be all Schwarzenegger-like, and played the game using both guns. My arms hurt like a bitch for days.
Street Fighter - Every iteration, especially Champion Edition and Alpha 2. The SFIII series, not so much.
Dance Dance Revolution - I got the most playtime on 3rd Mix over here, but I was able to play on the occasional 5th, Max and Extreme machines every time I went to the Valley Stream mall. Never could get into Pump It Up! though.
Other notable mentions: Pooyan, Frogger, Bubble Bobble, Cabel, Commando, Golden Axe, Mercs, Punch-Out!, Super Puzzle Fighter 2 Turbo, Darkstalkers, Final Fight, World Heroes II, Samurai Shodown I & II, Capcom vs SNK2, Capcom's Aliens vs Predator, Beatmania, and Guitar Freaks. If there's any arcade games I'm playing nowadays, it's Street Fighter IV and Espgaluda II. I really can't wait for my Tournament Edition FightStick to come in; being PC-compatible, I think I'll finally be able to relive some of that glorious old arcade feeling through MAME. :)