I hate Ipods. Apple is Evil. You'll find, if you buy an Ipod, that you'll need to use Apples music software, buy Apple peripherals, and buy music and apps for it. There's no practical reason to use an Ipod over any other MP3 player.
That being said, there
is a reason to have one. If your Granddaughter has a non-Ipod MP3 player, she will likely be considered quite uncool by her peers.
If you still wish to proceed with another brand, I'd recommend one of
these. I got a version of this way back in 2005, and still get complements about it. It is also super-easy to operate. No bogus software or music format requirements: It acts like a mass storage device. Just load on the songs, and it supports at least 5 major audio codecs.
Good luck!