One more option...
Instead of using a checkmark, use the cell in column A and format it to show a
check if there's something in that cell.
Select column A (A2:A65536 if you have headers in row 1)
format|cells|number tab|custom category
In the "type:" box, put this:
alt-0252;alt-0252;alt-0252;alt-0252
But hit and hold the alt key while you're typing the 0252 from the numeric
keypad.
It should look something like this when you're done.
ü;ü;ü;ü
(umlaut over the lower case u separated by semicolons)
And format that range of cells as Wingdings.
Now, no matter what you type (spacebar, x, anyoldtextatall), you'll see a check
mark.
Hit the delete key on the keyboard to clear the cell.
Now apply Data|filter|autofilter to your range.
filter by column A (to show non-blanks)
And if you have to ever find out if that row is "checked", you can use a formula
like:
=if(a1="","no checkmark","Yes checkmark")
You can just see if the cell is empty.