Donkey Kong - 194,000. I had 190k with THREE lives left. My personal best was clearly in my sights. Then, I died THREE times on the same L7 barrel board. So frustrating!
Asteroids (5 lives) - 29,910
I'm a 50k player on Asteroids, but here it took me quite a while to even get this score.
I hope everybody is actually using the correct ASTEROIDS (REV 4) rom and not just artificially limiting themselves to 5 lives using REV 2 or, even worse, REV 1. I bring this up because my romset did not contain REV 4, and I had to go out on the net to find it.
No question, there are more differences in REV 4 than just the 5-life limit. It is considerably harder than REV 2, most notably because the mini-UFO's are smarter. In REV 2, the mini-UFO's always fire directly at you, meaning that if you don't have a clear shot at one, you can still survive by letting him fly by, while you hide on the side of the screen opposite the direction the UFO is heading. Since the UFO's bullets only go part way across the screen, eventually they will not have enough range to hit you, and you're safe.
Not so in REV 4. The same range limitations apply, but the UFO is smart enough to aim the other way and wrap his shots around the screen to hit you. Needless to say, this pretty much doubles the difficulty; I had several games where I was struggling to even get the first free life at 10k, and it took me a while to figure out why.