I love
Margaret for the nicknames.
Madge,
Midge,
Mamie, and
Peg are my favorites. Especially
Madge. One time I even thought up Gari (
Gary) as a nickname, but that's neither here nor there. :x
Margaret by itself is kind of dour and frumpy, but in a way that's respectable and still leaves a little room for fun. It's a nice name.