If you're
really into progressive/rock and instrumentals, but like more modern groups, try searching the bands "Porcupine Tree" or "Riverside" on
Pandora Radio (If you haven't heard of it, Pandora offers you similar music based on how you rank the previous song you heard, narrowing results to your preferred style of music). These two bands have singers, but they actually provide harmony to the music, which can't be said for a lot of modern artists. Plus their instrumental work is outstanding.
I guarantee if you start with these artists, you'll find something you like.