Thought I'd tag this.
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim iColor As Integer

'// Note: Don't use if you have conditional
'// formatting that you want to keep

'// On error resume in case user selects a range of cells
On Error Resume Next
iColor = Target.Interior.ColorIndex

'// Leave On Error ON for Row offset errors
If iColor < 0 Then
iColor = 36
Else
iColor = iColor + 1
End If

'// Need this test in case Font color is the same
If iColor = Target.Font.ColorIndex Then iColor = iColor + 1
Cells.FormatConditions.Delete

'// Horizontal color banding
With Range("A" & Target.Row, Target.Address) 'Rows(Target.Row)
.FormatConditions.Add Type:=2, Formula1:="TRUE"
.FormatConditions(1).Interior.ColorIndex = iColor
End With

'// Vertical color banding
With Range(Target.Offset(1 - Target.Row, 0).Address & ":" & _
Target.Offset(-1, 0).Address) 'Rows(Target.Row)
.FormatConditions.Add Type:=2, Formula1:="TRUE"
.FormatConditions(1).Interior.ColorIndex = iColor
End With

End Sub