I'm historically more of a console gamer, and usually opt to play games on console when I get the chance (filthy casual, I know), but here are some of my favorites:
Diablo II: Diablo II is so ingrained into my mind that when my inevitable Alzheimer's sets in and I forget my own children, I'll still remember the sound of high-quality gems dropping from giant pixelated bosses. The tone of that game just felt perfectly gothic horror. The black and red color scheme and the dingy looking passages looked great, and left enough to your imagination. That game really did everything right, and its technical limitations really sold its atmosphere. Diablo III kind of proved that its charm couldn't be replicated.
FFXIV: I know this game gets a lot of hate from MMO fans, but as a lifelong Final Fantasy fan, it's a dream. Each expansion is its own 200-hour story, so it feels like a series of long RPGs more so than an MMO. It might be my favorite FF game behind Final Fantasy Tactics. I think the loot system is kind of uninspired, but the worlds look great, the music is top-tier, and the story is quite good. Even if it's not always on target, you get so much time with these characters that you want to just keep going on adventures with them.
Fortnite: Again, put down your pitchforks. Fortnite is an incredible game. I think its extreme popularity has turned a lot of people against it, but I think it's under-appreciated for how and why it got to be so big. Epic basically crammed PUBG into their failed fortress defense game, and then perfected the gameplay loop. While I think PUBG and a few other Battle Royale games are better tactical shooters, Fortnite just nails the experience and gives players a reason to come back regularly. I wish PUBG would learn from Fortnite's best qualities, like its monthly map shake-ups and constant stream of new mechanics, and not its season pass structure (which is fine, but PUBG really really failed to execute on this). I only wish
Fortnite scrims were handled through custom matches and not through Discord snipes, because playing Fortnite with 99 other hardcore players is awesome, and more people should have the opportunity.
Dark Age of Camelot: This was the first MMO I ever played, and even with my rose-tinted glasses, I think it was an incredible game that was way ahead of its time. Most of WoW's best features early on were lifted directly from DAoC, but they were simplified and candy-glazed in a way I could never get behind. I think the pace of DAoC probably wouldn't work for most people today, because it did have a lot of downtime, but everything just worked really well and had interesting mechanics. Games like ESO have borrowed heavily from its PvP setup, and the upcoming Camelot Unchained is basically going to be all about that. If DAoC hadn't been effectively killed by WoW, it would have been really interesting to see where they would have gone with it.