Replying to: Soph
I often do this.
Copying the 1024px layout in a separate IE 7 - 8 CSS file called with conditional comments doesn’t seem efficient to me (more files to load, a hassle to maintain).
I’d rather have the 1024px layout as a base, avoid loading heavy resources in it so that mobiles don’t have too much to load, and use MQ for smaller (mainly for layout) and bigger screens (for layout and high-density resources).