A really fast way to select huge runs of data in columns or rows quickly without picking up unwanted cells. Way faster than clickndrag selecting and more targeted than selecting the whole spreadsheet's column or row.
**UPDATE Additional Info** If your data range selection with this trick does hit a blank cell and stops, you can just tap the direction arrow a couple times to get past it, then take your fingers off the keys and hit the three button combo again to resume selection to the bottom of the data or the next blank cell.