No Doubt had been an adventurous rock outfit, but Gwen Stefani was free to explore a wider range of curiosities on her solo debut. With “Cool” and “Crash,” she nods to ’80s synth-pop and freestyle, but vintage quirks blend easily with modern glamor. Whether collaborating with The Neptunes (“Hollaback Girl”) or Linda Perry (“What You Waiting For”), she finds a reason to celebrate all styles. By pairing the giddy fun of New Wave with hip-hop’s muscle, Stefani throws a party that pop fans from every era want to attend. The Deluxe Version tacks on remixes and a live cut.