EXAMPLE: Panty and Stocking really didn't have much of a plot. And even if it did, it would probably be something immature as most of the show is. But the shows characters keeps people enjoying the show, I know I did

Both are obviously important, but interesting characters are what generally keep me interested. I can't appreciate a shows plot if I don't care for any of the characters.

Characters are what attract me to shows.

Actually both are equally important in anime.

Quality wise, it'll be the plot. Enjoyment wise, it'll be characters.

Sometimes the plot will arise from the characters (this is the case in most shoujo and jousei anime).

Tokyo Ghoul is a good example of this poll. The plot was really creative, but thanks to the characters, I wasn't able to enjoy it that much. The only characters I found interesting were, of course, Kaneki, Rize, Tsukishima, and that one boy with the white hair and stitches (I think it was "Jouzo" or something).