I wear sweatshirts almost all the time. I find it so versatile and love the combination of the dressed down look of a sweatshirt together with flat front trousers and crisp sneakers. It´s the most comfy piece of clothing I own, so invest in great quality pieces as these will get the propper use ;)
Here is some of my favorites, both with prints and the all clean versions. Brushed or unbrushed loopback.
Click the images for links to buy these.