There are multiple bands with this name.

1.Valentine Romanski, known as “Valentine” (born June 22nd 1988 in Zwenkau, Germany) is a german Singer and Musician. Her songs are mostly selfwritten Ballads where she also supports herself with the Piano.

The First Single “Feel So Bad” was very high in the german Charts in 2005. Her Debutalbum “Ocean Full Of Tears” was released some weeks after the Singe. Even Sir Paul McCartney was impressed by her and her talent: “This girl is amazing.”

2.Valentine is an AOR band from USA.
Hugo — vocals
Adam Holland — guitar
Craig Pullman — keyboards
Gerard Zappa — bass
Neil Christopher — drums

It’s self titled debut album was released in 1990. In 2008 second album, “Soul Salvation”, was released.

3. Valentine is a local band out of Las Vegas, Nevada. They have released one EP.

Emily Ellis — Vocals

website- www.myspace.com/valentineband

4. Valentine is also a name used by Dutch singer/multi‑instrumentalist Robby Valentine