Katniss Everdeen & Peeta Mellark

The star-crossed lovers from district 12

In my opinion Katniss should choose Peeta. To be honest I don't see why she even should think about choosing Gale...

Peeta loves her. 

And she loves him,

the boy with the bread.

I think that since the beginning there's a relationship between Katniss and Peeta. They're soulmates even if they don't know it for real. Peeta has a little idea of it. Because he noticed her the first day in school, he gave her the bread and thereby new hope, he looked after her all the time and she- to be honest- too. There's a thing between them they can't understand themselfes. Before they go in the arena they care for each other with a bit of suspiciousness, mostly from Katniss, because they know that saving the life of the other means dying oneself. Peeta ignores it. He saves her every single minute during the Games: he teams up with the Careers to guard her, he risks his life by letting her escape after the tracker jacker attack, he almost dies for her.

And she also loves him: she has a bad feeling when she thinks of killing Peeta, she feels betrayaled as he wants to be coached alone, she feels ashamed as he tells whole Panem about his love for her, she calls out his name instantly after the rule change, she cares for him even if she doesn't have any sense of what she's doing, she risks her life for him at the feast, she freaks out as she thinks he's dead.

And all the time she tries to convinse herself that it's only for the audience, only for the Games. Because she can't believe that she, a girl who nearly has no feelings or who never ever shows feelings, fells in love with a tribute. 

Therefore she always compares Gale and Peeta: she wants to find a reason why she likes Peeta. But after a while she notices that Peeta and Gale are totaly different and this is the beginning of her realizing her real feelings for Peeta. After their first "real" kiss she knows it, she admits that she feels save in his arms but then she makes herself forgetting it. 

Nevertheless she knows that she doesn't have the same feelings for Gale because she knows him for years and never even got the idea that Gale could be more than a friend. But with Peeta...

I think at their way back home to the District Katniss tries to protect herself and wants to keep Peeta at bay by telling him that she doesn't know what was real.

Why?

Because she fears that she could have REAL feelings for Peeta, that he's important for her, without the Games, too. She fears that she could lose again someone she really loves- Peeta because she has no idea what the love between them means for the real life, and Gale because Peeta is more important for her than Gale and because she doesn't know what feelings he has.

But with the last sentence it's obvious which feelings are true :

"I take his hand, holding on tightly, preparing for the cameras, and dreading the moment when I will finally have to let go."

Suzanne Collins, The Hunger Games, last sentence