In Excel 2010, if you are seeing extra blank lines (or white space) in your rows, once you have selected the entire row and clicked on "Autofit Row Height" in under the Format icon on the "Cells" Section of the Home Tab and you have confirmed that no cells in that row have entries that are not showing in the screen that could be causing this issue, try this step that was causing my issue:

1. Double-click on each cell to edit that cell and put your cursor at the end of the last character in the cell and use the "delete" button several times.
2. Do this for all cells in the row.
3. Then click outside the cell.
4. Go back to the "Autofit Row Height' and click on it to see if the row is now properly "condensed."

This is particularly important if you have been copying/cutting & pasting your data from other sources (rows in same worksheet, or in other workbooks, etc.) Many times there are "hidden" new line markers that Excel is seeing but are not visible to the end user.