Here is a band that I have just been introduced to (and plan on checking them out thoroughly), Premiata Forneria Marconi, or PFM. According to the wiki, this Italian progressive rock band has been a pioneer of international prog rock, being one of the first bands to use synthesizers, classical and Italian musical influences in the form of a 4 piece band.
The song I am linking you to (embedding is disabled) is off their 2006 Stati d'immaginazione, which is a completely instrumental album that focuses on the moods and emotions that the listener experiences. This is an eight-minute song, a length that's not unusual in progressive music, but is definitely worth the ride. This is music that is best enjoyed by dedicating time exclusively for listening. Check it out here