iPad - What are you guys doing on your iPad?

I'm going to buy an iPad Air and I'm curious about what capacity I should go with.

16GB are too less anyways, but I can't decide between the 32 and 64GB. (128 is not an option haha)

Besides that I am definitely going with the Wifi-only model.

I have about 20GB of music in my iTunes library (not using Spotify or Pandora or anything similar). But I simply don't know if the iPad will be a device were I store my music on (Also have iPhone 5 with 64GB).

My question is.

Do you use your iPad as a Music player (probably not in the train or anything, but at home)?

Also. What capacities do you have and how much space you use on your iPad?