I miss the aspect of them being playable by just about anyone, with or without video game experience. There wasn't a huge learning curve to get into Frogger or Tetris or Super Mario Brothers. I didn't have a console until I was 16, but my cousins had an NES, and there were plenty of days when 8 kids sat there waiting for our 'turn'.
I know things like the Wii and the xbox & ps platform equivalents are making strides towards getting back to that sort of 'group' activity, but it's not the same, in my opinion. Yes, it's hilarious watching Uncle Al try to outbox his 10-year-old nephew and send the nunchuk flying, but... I dunno. Not the same as Nana hunkering down with the old brick NES controller and making it to the end of a level and letting loose with the swear (sonofabitch!) when she's knocked out by a koopa. Scandalous!