1. Heroes of Might and Magic Saga (H3 being the best)
2. Final Fantasy Saga (only from I to X)
3. Crash Team Racing
4. Monkey Island Saga
5. Smash Bros Saga

Daggerfall and Skyrim are my favorite. Oblivion was not so good. I found the monster level scaling annoyingly stupid...
Sadly, Daggerfall is buggy to the aextent of being unplayable without debug mode but it just has *atmosphere*.
CTR! Yeeeaaah!

1-Heroes of M&M6
2-Balder's Gate
3-Neverwinter Nights
4-The Witcher
5-Anno 1404 Venice

Not enough Mario three on these lists folks.

Yes, I love CTR too! So many good times!!
And, yes, I love Skyrim and Daggerfall best too! :D :D :D

1) Fallout 2/New Vegas
2) Pokemon Emerald
3) POD Gold
4) Skyrim
5)Terraria

1. UFO: Enemy Unknown (aka X-COM: UFO Defense)

2. The Secret of Monkey Island

3. Little Big Adventure

4. No One Lives Forever

5. Uh...uhm....can't decide, impossibru!!

1 X-men Arcade
2 Turtles in Time
3 Star Wars Kotor 1
4 Medal of Honor [1999]
5 Indiana Jones and the Fate of Atlantis.

Most definitely. 1 & 2 together make the whole story. Sam Lake writes in the same film noir style, continuing where the first one left off, taking you through a comic and tragic emotional wringer that resolves in a classic denouement, tying up all the loose ends. But, the gameplay, the gun play and the level design leave you wanting more.

I often neglect my backlog because I'd rather take an hour to replay my favorite levels. But this is not tragic. :)

1) Mega Man Legends
2) Super Mario 64
3) Toonstruck
4) Threads of Fate
5) Wolfenstein 3D/Spear of Destiny

I don't like multiplayer, even when it's with people I like.

Arcanum
Deus Ex
Oblivion
Planescape: Torment
Fallout 2

runner ups:
Civ IV
Doom II
Dragon Age: Origins
Skyrim
Fallout: New Vegas
Civ V

As you can see, i like really big games. The list is pretty much total play time.

Morrowind
Fallout
Deus Ex
Thief 2
Sam & Max Hit the Road

Those five games build pretty much the entire foundation of my gaming hobby and what I still enjoy today.

HI!

1. Half Life, all of it, specially Opposing Force and 2.
2. Age of empires 1 and 2, plus Steam HD version
3. Commandos series, BTEL + BTCOD + 2 + 3
4. Grand Theft Auto, all of it
5. Hitman, all the saga

I am not a multyplayer person, i do preffer a good single player history.

Off the top of my head...
(If it looks like I posted more than 5 your eyes are just playing tricks on you.)

PC
----
Secret of Monkey Island Series. I refuse to pick just one! :P
Thief Series. I refuse to pick just one! :P
Day of the Tentacle
Indiana Jones and the Fate of Atlantis
Grim Fandango
Ultima 7
Half Life

Retro Consoles
---------------------
Legend of Zelda Series - I refuse to pick just one! :P (Up thru Majora's Mask)
Metroid (NES)
Contra (NES)
Ducktales (NES)
Mega Man 2 (NES)
Simon's Quest (NES)
A Boy and His Blob (NES)
Raider's of the Lost Ark (2600)
E.T. (2600 - Yes, you read right!)

Newer Consoles
-----------------------
Grand Theft Auto 3
Borderlands + DLC's
Lego Games - I refuse to pick just one! :P
Little Big Planet Series - I refuse to pick just one! :P
Portal
Batman: Arkham Asylum
Minecraft (I have it on the 360)

Arcade
---------
Dragon's Lair
Donkey Kong
Frogger
Dig Dug
Bagman

tl;dr - List of PURE AWESOMENESS!