There would be fewer mountains and ocean islands. Earth would probably being a fairly boring planet and in many ways resemble the North Dakota landscape. As I just mentioned volcanoes have made the ocean, ocean basins, and atmophere. Without the water and other chenmicals released by volcanoes life probably would never originated on this planet. Volcanoes create islands for people to live on.
Volcanic deposits make fertile soils.
They are a great boost to the tourism industry. Also have a look at Question 17 in section 4. The Effects of Volcanoes in Ask a Volcanologist. The current status of the volcano is posted on the homepage of the Cascade Volcano Observatory. The most recent significant event was an increase in seismicity.