We've been through a bit of a nightmare singer wise in the top40 setup.
We had found a great guy who was really nu-metal and ready to move into that direction, but he left after 2 months due to another project with professional aspirations. Then we had another guy, and for the past 6 months worked with a female singer, who was good on some songs, but really lacked the timing, feel and stage presence. But she was a friend of the drummer, so we hesitated to kick her out. After a bad gig with drastic feedback from the audience (thank god) she left on her own.
Yesterday we auditioned a new female, a maroccan with fire and loves rock (we played some Zep and GnR in the jam too), she has great presence and is really into it.
I made a recording, I gotta add that I played over a Marshall Cab with G12T75s, which I don't like very much, plus the cab was pointed directly at the recorder, so the guitar is unfortunately over present and drowns out the rest a bit.
Let me know what you think about the voice:
http://www.klangforschungszentrum.de/temp/heavycross.mp3