If Dumbledore's visit taught him anything, it was that his usual way of getting what he wanted—pushing the other person to do or say something—wasn't going to work for him any longer, not in a world of people who could do the exact same thing back to him. So, when he went to the shopping centre, as well as his school things, he looked for information about his new world: History, famous figures, everything about the school he was to attend, and ways to protect himself from being forced to do things he didn't want to do.
It didn't take him long to discover two important things: Just as in the non-magical world, influence came from money and old connections, neither of which he had, but showing bravery and a sense of righteousness was nearly as guaranteed a way to get ahead. Which meant, his best option to climb to the top in the magical world, was to be brave and good. (And to collect as many allies in the shadows as he could.)
When he placed that decision against all he learned of the prejudices of the magical world and, more specifically, of the various Houses in Hogwarts, he determined that, should he have the opportunity to pick, he should very much prefer to be in the Gryffindor House.
And so, when the ratty old hat was placed on his head and said, "Well, well, you're an interesting one. A great thirst to prove yourself, to be the best, and a love of knowledge, as much for having it, as what it can do for you," he knew he had reached that chance to pick.
So he thought back, "I may be brilliant, and I may wish for great things in my future, but don't you think the most notable thing is the courage it takes to step into a new world of impossible things, when it would be so much simpler to remain with the world and strengths I already knew?"
The Hat hummed, low and thoughtful. "Courage? Yes, there is some in you. Enough to take risks, to push past obstacles in your way."
"Yes, exactly," Tom thought back, clenching his fists to keep from pushing the Hat. Assuming such was even possible. "I have courage, I can be daring, but without others around me of a similar mind, I might well let that turn rotten, until I'm half the man I might grow to be. But, in the Gryffindor House, surrounded by others willing to risk their lives for the betterment of magical-kind..."
"An unusual argument, young man, but an intriguing one; Slytherin and Ravenclaw would both suit you best, but you intend to play to your weaker aspects."
"Yes," Tom agreed. And then, because he'd learnt his lesson about putting on a polite face from Dumbledore's visit, he added, "Please."
"Yes, I think it will be interesting to see who you become in GRYFFINDOR!"
Tom removed the Hat and handed it back to Dumbledore, avoiding his suspicious stare, then made for the table that was screaming for him.
At least red and gold suited him.