Baldur's Gate, yo. And the old SSi Gold Box games like Pool of Radiance, Curse of the Azure Bonds, Secret of the Silver Blades and Pools of Darkness. I spent AGES playing Secret of the Silver Blades, because of the place in town where you could cache your treasure. By the time I'd stopped playing, I had 3 sets of +5 Plate, +5 Shields and +5 Swords from some of the hardest baddies in the game. Which means I played that game through at least 10 times.
I also played SSi's Dark Queen of Krynn, the one that took players to the other continent of Krynn. And Crystal Quest. Man, that game got incredibly frenetic at higher levels!, and let us not forget the original Tetris, and Dungeons of Daggorath for the TRS-80 (we're talking REAL OLD SCHOOL here!).
One of my favorite old games, which I still play today on the DOSBOX emulator is Master of Orion 2. And Civilization, yes, the original. All of which I first played on my old Macintosh LC, my first computer. And Dragon's Lair. Thayer's Quest. Space Ace (first games to incorporate laser disc technology). Golden Axe. The Original Gauntlet. Battlezone (okay, that was an arcade game, but still...)
I'll cut off here, before this becomes a Tl;dr.