I have a pair of Descente arm warmers that fit really well for slender women's arms.

I like waring leg warmers on my morning commute in the summer. It's often 45 degrees in the morning and 70 when I bike home, and just packing the warmers instead of an entire pair of knickers on the way home saves me a lot of room.

I guess it depends on what your riding situation is. I usually don't wear leg warmers on weekend recreational rides, but they're just the thing for chilly summer morning commutes.