Re: Which world #5 is the best player at her peak? Hantuchova, Chakvetadze or Kerber?
Chakvatedze in her best year ever (2007) was probably the 8th best player in the World behind Henin, Serena, Sharapova, Venus, Kuznetsova, Ivanovic, and Jankovic, regardless of her ranking of #6 above Serena and Venus she was obviously not better than at the time in reality.
Hantuchova in her best year ever (2002) was somewhere from the 8th best player in the World behind Serena, Venus, Davenport, Sharapova, Mauresmo, Capriati, Clijsters. Some might disagree but I think by years end she had surpassed both Hingis and Seles in present ability, and was also ahead of Dokic and Rubin, even though Rubin had probably her career year that year. I believe her year end rank like Chakvetadze was higher than that, but WTA rankings are often meaningless anyway.
Kerber right now I would say is the 9th best player in World behind Serena, Sharapova, Azarenka, Radwanska, Stosur, Errani, Na, and Kvitova. Again not as good as her actual rank suggests.
So at their best all held roughly the same position in the game. Hantuchova held this position at a much tougher time for the womens game though. The 2002 field > the 2007 field > the 2012 field, and with all holding basically the same position in the game by extension peak Hantuchova > peak Chakvatedze > peak Kerber.