Bernhard Jenny let me know about his GISLook and GISMeta add-ons to the Mac Finder; they’ll be added shortly to my previously-published list of Mac GIS freeware.
GISLook adds preview capability to GIS data to the finder, supporting:
Vector data
• ESRI Shape (.shp)
• E00 ArcInfo Interchange (.e00)
• ArcInfo Coverage (.adf)
Raster grids, such as digital elevation models or land cover data with a single band
• BIL (.bil), BIP (.bip) and BSQ (.bsq) with .hdr file
• ESRI ASCII Grid (.asc)
• ESRI Binary Grid (.flt with .hdr file)
• PGM (.pgm)
• SRTM (.hgt and .dem)
• Surfer Grid (.grd)
• USGS DEM (.dem)
GISMeta lets you see the size of raster data files in the Finder.