Pretty much anything from Ellis' Excalibur run, especially from #86 onwards, spotlights Kitty well. If you get get hold of it, the Pryde and Wisdom miniseries too, which is just full of love and Kitty and Pete Wisdom bouncing witty dialogue off each other while staying true to character (unlike Whedon's humor, which tends to rely on characters saying or doing something entirely out of place for lols).