I told everyone at work I didn't WANT a second shower, that (same reasoning as above) I already had all the baby things, clothes, etc. My second was a boy too, so the clothes were even the "right" colors <g>. But, they chipped in and got me a double stroller, which turned out to be a great gift, as I used it a lot!
Getting little-girl things for people is fun too. Let's face it, boy clothes are not as pretty!! She might appreciate a little start on outfits, some diapers that will fit (the new baby, not her), or, as has been mentioned, a gift certificate. Maybe some company has come out with a "new and improved" version of something she would really like, but didn't have for the first baby. And it's nice to get the older child something too, so he doesn't feel left-out.
The "freezer meal" shower sounds like a great idea too! Very thoughtful. (she WILL be tired. I always maintain, after having the second child your life is NOT twice as busy; it's TEN TIMES as busy as it was!!!) Congrats to her and you'll decide what's right.