The only bummer is that the rovers' sound gear broke and we still can't hear the sounds of the Martian surface.
It would sound very windy. Mars is smaller than earth, but its atmosphere is much higher and thinner than ours and is composed mainly of carbon dioxide. Its atmospheric pressure is about 0.6% of earths. This is not enough pressure to support liquid water at the surface, so any water ice vaporizes before becoming liquid water. Being that liquid water is not supported on the surface of Mars, the weather patterns are mostly influenced by surface temperature. On earth, weather is greatly influenced by the differences in heat and moisture content of both land and sea, so we get rain storms. As Mars has no surface water, heat stored in soil and rocks that interacts with cooler air creates wind and dust storms. Being that it doesn't rain on Mars, the dust can remain in the atmosphere for very long periods and also contributes to the variance of surface temperatures in localized areas. This give us more wind.
Mars has a very low thermal inertia (ability to maintain temperature), so its surface temperature varies greatly daily, as much as 100K. During perihelion (closest to the sun), Mars receives about 40% more sunlight than aphelion (farthest from the sun), resulting in more dust storms. During aphelion, water ice forms in the Martian atmosphere bonding with dust particles and forming very thin, whispy clouds. The clouds prevent sunlight from heating the surface as much, so wind is reduced, and it is extremely frigid. But again, the main output of all seasonal changes at the surface once again result in wind.
While I would love to think that if the rovers audio worked we would hear a Martian drummer somewhere working on paradiddles, or better yet playing Moby Dick, I'm afraid the only sounds we will really get are the mechanical sounds of the rover, and wind.