In no particular order. Here's what I come up with:
1. Eight Ball Deluxe, Bally, 1980/81, a classic that well represents what "pinball" is.
2. Xenon, Bally, 1980, excellent artwork, theme & design, speech & sounds, + multiball.
3. Joker Poker, Gottlieb, 1978, a classic great action drop-target game, 3 flippers, cool artwork
4. Fathom, Bally, 1980/81, Wow!
5. Skateball, Bally, 1980, Love it, gotta have it someday!
6. Paragon, Bally, 1979, This widebody has it all.
7. Firepower, Williams, 1980, another great machine from one of the greatest years in pinball ..1980
8. Iron Maiden, Stern, 1981, Holy Grail #1 pin for me, ...never even seen one up for sale.
9. Asteroid Annie & the Aliens, Gottlieb, 1980, Holy Grail #2 pin for me, hopefully someday.
10. Black Hole, Gottlieb, 1981, cool game
11. Nitro Ground Shaker, Bally, 1978-1980, gotta turn it up to 11! ...Sorry, I want one badly.
Honorable mention:
* Barracora, Williams, 1981, possibly too many drugs consumed in the late 70's/early 80's led to this unique artwork. Great playfield layout.
* Silverball Mania, Bally, 1980, great backglass artwork
1979 - 1981 were busy times in the pinball industry.