1. Minecraft
2. Super Smash Bros. Brawl
3. Portal 2
4. Need for Speed: Most Wanted (2005)
5. Burnout: Paradise or NFS: Most Wanted (2012)
This was really though to think about. I'm sure I will change it later if I make up my mind officially.
This list has definitely changed over the past 2 years, although it's still hard to think about. I have a LOT of games in mind that I have some great memories with, but for this list I think I have to base it on a combination of sheer hours, replayability, nostalgia, and if the game has affected me in the real world at all.
1. Minecraft
I've easily put thousands of hours into Minecraft, and probably 90% of that play time is on servers. I've owned the game since July 30, 2012 and I
still occasionally play it to this day, although not nearly as much as I used to. I have some great memories playing on servers that had close knit communities, including my real life friend's server which I now manage when I can. I genuinely miss when servers felt more "personal", instead of it being dominated by massive servers filled with microtransactions and premium accounts. But even still, this game will always be close to my heart.
2. Star Wars: The Old Republic
I could find out how much I've played, but that would require going onto my 12 characters and typing a command, and then adding all of it together. But I'm sure it's more than 1000 hours. I started this game back in late January of 2015 and I've done a majority of what's in it, and it's a LOT considering it's an MMO. But I enjoy it so much because I love Star Wars, I love choosing my own dialogue, and the stories in it are fantastic. I really wish it was all canon.
3. Portal 2
Between PS3 hours and Steam hours, I probably have close to just 100 hours for Portal 2. I remember the first time I played through the story on my PS3 when I still had it, and I was blown away by how good it was. So many memorable quotes, ingenious gameplay, and damn good multiplayer that a good friend and I did together on splitscreen. I could easily still get enjoyment out of doing the story another time or 2.
4. Rocket League
At 381 hours and counting, it's my second most played game on Steam (behind clicker heroes, but that's not even in my top 10). The gameplay is a blast, and it's a staple game that my friends and I play while Skyping. It definitely has its frustrating moments, but it's such a fun game that I don't think I'll quit playing it any time soon.
5. Super Smash Brothers Brawl
If memory servers me right, I had over 500 hours into this game when I had my Nintendo Wii, and man what a great game it is. I can even play it today still using a Wii emulator on my PC, and I do if I'm in the mood. The combination of the excellent story mode, fighting elements, and replayability means I'll never forget it.