Pros: Comfortable, Well-made, Ventilated
The Giro G10 is a well-made, solid ski helmet with adjustable ventilation. It has a removable padded liner, and Giro's adjustable (but non-removable) sizing adjustment system. Assuming you get a size that fits your head, it's quite comfortable. With the vents closed it's pretty warm, and with them open it breathes pretty well. This (and the very similar G10MX) come in a wide variety of colors and patterns, so you can find something that will match with (or garishly clash with) your outfit.
The only downside? It's a little expensive for what you're getting.
I don't have a whole lot else to say -- it's a helmet, and it should keep your head in one piece if you smack it into something. If you don't want to spend quite as much, you can definitely find some cheaper alternatives.