How to easily reorder rows in excel with drag and drop or move-up or move-down?

1. Select the row/column.
2. Move your mouse cursor to the row/column's boundary so that you see the four-way-arrow cursor (or hand cursor on a Mac).
3. Press Shift on your keyboard, then click and drag the row/column.

The Shift key shifts the row/column instead of overwriting the target row/column.

This is still a cut/paste method, but is the simplest way I can think of.

4-click solution: (eg. move row 8 above row 5)

1. Right click row number (eg. row 8), click Cut (or T)
2. Right click row number (eg. row 5), click Insert Cut Cells (or E)

Note: This also works for moving multiple rows.

Add the following macros to your Personal Macro Workbook and assign them shortcut keys. The behaviour mimics Sublime Text's Swap Line Up & Swap Line Down.

Sub move_rows_down()
    Dim rOriginalSelection As Range
    Set rOriginalSelection = Selection.EntireRow
    With rOriginalSelection
        .Select
        .Cut
        .Offset(rOriginalSelection.rows.Count + 1, 0).Select
    End With
    Selection.Insert
    rOriginalSelection.Select
End Sub

Sub move_rows_up()
    Dim rOriginalSelection As Range
    Set rOriginalSelection = Selection.EntireRow
    With rOriginalSelection
        .Select
        .Cut
        .Offset(-1, 0).Select
    End With
    Selection.Insert
    rOriginalSelection.Select
End Sub

For snobs like me who want to use keyboard only:

1. Select the cells you want to move (rows or columns, or any rectangle of cells, but the selection must be contiguous)
2. Press Ctrl+x (Ctrl+c would let you make two copies.)
3. Move to or select the cell immediately after where you want to move the content (below it, or to the right.) This cell will not move.
4. Press Ctrl++. This will shift cells down or to the right. (Ctrl+v would overwrite cells instead.)

On the Mac, all of these shortcuts work the same with either Ctrl or ⌘.