Ghost Love Score is probably the pinnacle of symphonic metal. But there is a lot of other good songs and bands in that genre.
Nightwish is probably the most well known. They had 3 singers:
1. The first being Tarja Turunen. Great opera trained singer.
2. After the breakup with Tarja, they hired Annette Olzon but she did not have the talent that was needed to fully replace Tarja. Many people still liked her.
3. Then they hired Floor Jansen which was singing for other metal bands beforehand. She has by far the best voice in my opinion.
Edit: The term often used on hearing Floor Jansen singing is having a floorgasm 
