I listen to Imogen Heap quite a bit. Her albums are officially in the Alternative genre, but her songs have this techno-pop feel to them with a nice beat, and can be very sexy. Her albums have been a big success in the US.
Imogen has a soft and sweet voice, like Alizee. I liked where Alizee was going in Psychédélices with Décollage and Par Les Paupières, but the rest of the songs kind of lost me. When I listen to Imogen, I imagine Alizee singing the songs and how perfect a fit this style would have been for her at that time in her career.