I believe you'd want the carriage return if you were copying more than one cell, which is probably why it's being included.
But if you're copying one at a time, you can copy from the formula bar instead of from the cell then you won't get the carriage return.
If you have a lot of cells to copy, you might want to create a simple VBA script to push the contents of the selected cell into the clipboard (then assign that to a hotkey).
Edit:
Example macro:
Sub CopyActiveCell()
Dim objData As MSForms.DataObject
Set objData = New MSForms.DataObject
objData.SetText ActiveCell.Value
objData.PutInClipboard
End Sub
Note that for that to work you need to add a reference to Microsoft Forms 2.0 Object Library
(via Tools | References). If you're copying many values, you could make it even simpler by adding creating the sub in the Sheet1 module as
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
instead of
Sub CopyActiveCell()
That will automatically copy the cell value whenever you click once on a cell to select it.