Best apple tablet device to get for my girlfriend?

So I'm a tech guy but I'm not too familiar with specs and pricing for iPads including the mini series and air series. I guess what's probably the best bang for my buck. She wants a bigger screen and I was thinking maybe mini would be okay but I want it to be 1080p but I'm not sure if the mini goes that much. I don't think I can spend over $500 and close to $300 I guess is what my limit is. I'm a college student I'm not trying to cheap out cause I know how tech works and I know apple ain't cheap. Anyways I was think iPad air 1 or maybe mini 2 or 3 but I don't know how much the mini 3 costs. It's for her birthday which is in a month but hopefully I can get her something she likes. I guess 64 gb out 32gb if there are 32s, is what I'm going for. 16 would probably work but I just wanted to get her a lot of space just in case but i don't know if she'll use it. She wouldn't use it to take pictures… Hopefully. She has a Mac air, iPhone 5s that's why I'm getting her the iPad. She wants a bigger and better resolution screen basically that's more portable.

Personally I like the iPad mini I can remember the price but I've had it over two years and it is in really good condition so I wo get the iPad mini

What I would do is get her a gift certificate for up to the amount you are willing to go and allow her to pick out the device she'd want. This way she can just use the about you put on the gift cert or she can add to it and get something that costs more. And then you don't limit what she could have gotten had she had the option to pick herself.