Christina Aguilera, "Not Myself Tonight"
In the four years since Christina Aguilera released her last studio album, "Back to Basics," pop ingénues like Katy Perry, Lady Gaga and Ke$ha have built their careers on bold theatrics, neo-feminist personas and throbbing club beats. Aguilera brings all of that to the table on "Not Myself Tonight," her lead single from the upcoming "Bionic," but ups the stakes considerably with her trademark, octave-straddling runs and glory notes. Aguilera channels a more Euro-glamorous version of her former "dirrty" alter-ego Xtina on "Tonight," dashing lyrics about self-reinvention with breathy chants and naughty expletives. Producer Polow Da Don, who co-wrote "Tonight" with "Drop It Low" singer/songwriter Ester Dean, adds dripping synths, pulsing basslines and tribal house drums that sound appealingly unfinished. Paired with Aguilera's unmatched vocal range, "Tonight" proves that the current dance-pop craze would be incomplete without her. -Michael Menachem