I have several favorite video games myself, having been born in 1979, I was just old enough to remember the Atari era, and the right age to get in on Nintendo when it came out.
That being said, I have a top three of all time favorites, spanning from different times:

#3: The Legend of Zelda: Ocarina of Time

Not only was the soundtrack amazing, it was rather soothing to listen to, especially the opening theme. I've found a version of it played on a piano that is breathtaking. As for game play, it was such a vast and adventurous journey, myself and two other friends teamed up to finally beat it: one was in charge of all things combat related, one was in charge of solving the puzzles, and one was reading the guide aloud and directing the other two. Also, I learned how to play the theme from Beverly Hills Cop on the Ocarina, which I often did after winning a battle lol.

#2: The Witcher 3

Again, I am a sucker for a beautiful soundtrack, and the entire score written and performed for this game was outstanding. I was thrilled to have received a separate CD of the soundtrack, as well as a map to put on my wall. As for the game play, the fact of it being derived from a novel series thoroughly intrigued me, and the visuals and combat were flawless. A dark fantasy world, and you are a lone warrior, older and grizzled, plenty of scars from the literal hell you've been through in life. I could relate to Geralt of Rivia on many levels, and the dark humor associated with the game's writing had me laughing out loud several times. My first play through led me to an ending in which had me in tears, because of how well the game itself had engaged me and had me emotionally invested in the characters. It sparked me to search for the novels, and I've read all but the last one so far.

#1: Assassin's Creed Origins

Everything about this game has had me in awe from the day of release. I generally don't ever pre-order a game, but after having done thorough research about this title, I put my pre-order in for the deluxe edition (again something I never do) in July, four months before it would be released. When I finally got my copy, I was blown away with the visuals, the extreme attention to historical detail, the fluid combat system, and the character developments and relationships. Ancient Egypt is one of my favorite historical time periods, and the Egyptian art and architecture have always been a draw to my eye. I've spent hours on this game just wandering around some of the towns and looking at things, as if I were on a virtual sightseeing tour. While playing this game, I feel Bayek's duty to the people, and anytime I see Romans mistreating the Egyptian or Greek citizens, needless to say they are dealt with quite harshly, whether it's with blade or arrow. This game also does an outstanding job at having me emotionally invested in the characters, both main protagonists and supporting characters, no matter how big or small.

Those are my top three and the explanations as to why they are my favorites. Have a great day!