In no particular order
1.
Rollercoaster Tycoon: (What a surprise)
2.
GTA - Vice City: the 80s Atmosphere and the soundtrack are superb. Not to forget LoveFist.)
3.
GTA V: Story and Characters are not as great as in GTA 4 (Brucie was the best

) - but all in all GTA 5 is the better game. Great Story-Telling, great Characters, a huge and beautifully designed world, a great "holiday"- atmosphere and a good soundtrack.
4.
Monkey Island 1 - 3: Great Point and Click Adventures. Hard to make a favorite out of these three. Great puzzles, great humour - great games. But Monkey Island 4 was pretty bad.
5.
Grim Fandango: A masterpiece

6.
Broken Sword: One of my favorite Adventure games. Suspense, Thriller and Adventure mixed with great, subtle humour.
7.
The Walking Dead (Season 1): I don't like Zombie-games...I find zombies pretty boring but this game is really, really good.
8.
Super Mario World: My favorite Mario game.
9.
Zelda - Link to the Past and
Ocarina of Time: Both are two of the best games ever made.
10.
Conkers Bad Fur Day: What a weird game...what a perfect game.