Other apple varieties for a Granny Smith fan
Granny Smith's popularity as a baking variety is mostly due to its firmness and tartness, which will offset the caramalized sugars from baking the apple and prevents the apple from falling apart, but theres no reason you can't eat it plain as well. Actually I also prefer fresh apples which arent too sweet, and granny smith's are one of my favorites to snack on as well.

Now, there are hundreds of different apple cultivars (or varieties), and many will probably not be available locally, and you haven't mentioned what it is you like about granny smith apples, so I can't specifically reccomend that many apples.

That being said, I would cross reference wikipedia's list of apple cultivars with attributes you like in an apple, and see what comes up. For example if you like tart apples you could try Honeycrisp or Pippins. If you like firm apples try Golden Delicious, or Golden Gala.