If you're looking for a versatile look that is comfortable and casual yet still nice looking and professional, you can't go wrong with boys polo shirts. You can find these in popular brands like Ralph Lauren, Tommy Hilfiger and Lacoste and in just about any color you can imagine.

This style of shirt is often used for school uniforms or on the golf course, but it obviously useful and appropriate clothing for many other occasions.  The fabric used for polo shirts is usually either a cotton pique, cotton knit or some type of poly/cotton blend.

Another nice thing about these shirts is you can have them made into a custom embroidered polo shirt and use them to advertise your business or event or give away at a social function like a conference or expo.