I'm not sure if I mentioned this earlier, but I feel that I should now. The characters whose wands are not specified, I just made up.
Ollivander's Memoirs
Sirius Black
Mr. Ollivander lit the top of yet another candle with the tip of his wand. Even in sunny afternoon light his shop was very dim, so on an exceptionally stormy afternoon like the present, it was very difficult to see much in the store. Mr. Ollivander didn't expect many customers to fight the weather to come in, but should any come in he did not want the shop to be so dark the customer could not see which wand he or she was purchasing.
Mere moments after he had finished lighting the last candle, Mr. Ollivander heard the door open. In walked a young boy—tall for his age, dark hair and grey eyes, very handsome.
"Good afternoon, Mr. Black," Ollivander greeted him. This young boy was Sirius Black, yet another leaf on the Black family tree. Mr. Ollivander could recognize him, and his younger brother, Regulus, who followed not far behind him, anywhere. Sirius did not reply with words, but with a careless smirk. Next, Mr. Ollivander greeted Regulus, and received nothing, but a quick motion of Regulus' eyes looking him over. Mr. Ollivander rarely had time to observe the Black family, he rarely left his shop and they spent most of their time in their home, that's location was unknown to almost everyone in the wizarding community, or Knockturn Alley, but the few times he did, this was normal behavior for Regulus. Sirius was outspoken, loud, a talent for being a bit rebellious, while Regulus was always quiet, bearing the same expressionless countenance.
Next Mr. and Mrs. Black entered shop.
"Afternoon, Mr. Black, Mrs. Black," said Mr. Ollivander.
"Afternoon," Mrs. Black answered with a tone of condescension or disdain. Mrs. Walburga Black was perhaps a great beauty at one time in her life, to have such handsome children one would have to have been attractive, but the years had not been particularly kind to her. Although a hint of what once was a lovely face still remained, she was now very drawn and gaunt looking with her lips permanently formed into a line that inferred distaste. Mr. Orion Black was not in a much better situation. Although his hair had not begun to grey, his age was shown through the wrinkles in his skin and the large bags under his eyes. Like his son Regulus, Mr. Black seemed to prefer remaining quiet; however, unlike Regulus, there seemed to be something completely sinister and frightening about his silence.
"I presume Mr. Sirius is here to purchase his first wand?" asked Mr. Ollivander.
"Yes, Sir," answered Sirius. Mr. Ollivander nodded his head and disappeared into the rows of wand boxes. He read each box carefully. Some witches' and wizards' wands were easy to choose, but this boy was different. He was different from his family, Mr. Ollivander could tell. He wanted to be different. It would not be right to choose a Willow or a Walnut as those were the woods of his parents' wands. Unfortunately cores were limited. Scanning one the final rows of boxes he discovered what he believed to be the perfect wand for Sirius. He carefully slipped the box out from under the others and carried it to the front of the shop.
"Ash, dragon heartstring, twelve and a half inches," he handed the wand over to Sirius.
"Wicked," Sirius murmured quietly as he held the wand. Mr. Ollivander half-expected Mr. or Mrs. Black to examine the wand, make sure it was good enough for their son, but they seemed rather indifferent. Briefly observing them as Mr. Black paid for the wand, Mr. Ollivander noticed that unlike Sirius who generally remained paces away from his parents and walked ahead of them, Regulus always seemed to be closer to them, following them. At that moment he stood next to his mother allowing her to stroke his hair as he stared blankly at something in the back of the shop.
Mr. Black paid Mr. Ollivander and turned to exit the shop. Mrs. Black turned to follow. "Sirius, put that away before you hurt someone," scolded Mrs. Black, clearly irritated, who noticed Sirius making swift motions and flourishes with his new wand. Sirius rolled his eyes and slipped his new wand into his pocket.
"Common, Regulus dear," Mrs. Black placed her hand on Regulus' shoulder and guided him out of the shop. Mr. Ollivander didn't bother bidding them goodbye. They wouldn't listen or appreciate it anyway.
"Thank you, Sir," said Sirius who still remained in the shop pulling his wand back out of his pocket.
"You're welcome," Mr. Ollivander smiled.
"Sirius!"
Sirius again rolled his eyes and jogged out of the store. Mr. Ollivander couldn't help, but smile when seeing him. Here were the Blacks filled with false authority and self-importance and their own son didn't take them seriously. Despite his overall appearance as a somewhat rebellious teenager, Mr. Ollivander viewed him as one of the most promising members of the Black family. He looked forward to the day when Regulus would come to purchase his wand so he could see what became of Sirius. He had a feeling his time at Hogwarts would be differently spent than the rest of his family who secluded themselves mostly to gatherings in the Slytherin common room.