Title says it all, regardless of time released or system, whats your all time TOP 10?
Note: It doesn't mean that the 10th title on the list is SO MUCH worse than the first. They all are really close together, difference from 1st to 10th maybe being 5% in my personal appeal.

Note 2nd: This list doesn't contain too many Nintendo titles and fairly old games mostly, that doesn't mean I don't enjoy my Paper Mario or Monster Hunter, but they haven't been around for long enough to impress my "lifetime best of list" and of course they'd have to fight that Nostalgia! My top Ten in "recent years" would look completely different of course.

Mine:

1. Battlefield 1942 - PC - having matches with my mate and roughly 126 bots on a dedicated server in my network was THE thing! Loved it.
2. X-Com Enemy Unknown - PC - the Original, nothing beats it when it comes to strategy/tactic/research games. Loved the theme of it too!
3. Fire Emblem - various Nintendo systems - just love the tactical gameplay and Stories. Just. Love. it.
4. Halo Combat Evolved - XBOX - the Original, loved it.
5. Battlefield Vietnam - PC - a worthy successor to Battlefield 1942, loved every minute of it.
6. Mortal Kombat I & II - ARCADES / SNES - loved it as early teen. It was THE thing. Streetfighter go eat a tree!
7. Everquest - PC - I wasted too much time of my youth on this one to not include it on the list!
8. Super Smash Bros. Melee - GAMECUBE - no need to explain this!
9. Battlefield Bad Company 2 - XBOX360 - Loved the Vietnam Addon, best console shooter to date imho.
10. Blur - XBOX360 - too bad they stomped it. Like many good games/studios. It's like Mario Kart for grownups, love it!

Honorably mention, really there is no room anymore so...
Argh damnit:

11. MARIO KART - any

Im sure i forgot plenty...

Final Fantasy IX is #1. I just made my list really short to get to the good part!

Fair enough. To the point. Like germans. lol
I never liked FF though! XD

Well I loved it then. Things change though unfortunately.

Yep, i really wonder if its true: "it was better back then"
or is it just a universal, general misconception of... everyone?

Super Mario bros..NES
Nemesis...Arcade
Resi 4...gamecube
Sabre wulfe...cpc 464
Commando...arcade
Cobra triangle...NES
Cod modern warfare...Xbox 360
Blast corps...n64.
Goldeneye...n64
Contra spirits..super famicom.
And numerous others...

1. Whatever the newest RPG version entries in the Pokemon series are. Will this soon be X or Y? Undoubtably.

2. Metroid Prime Trilogy - This might be a really cheap inclusion considering it's an anthology, but all three games, even as stand-alones would be in my Top 20, and the Wii controls added to already-perfect games make these the ultimate version. There is nothing I do not like about the MP trilogy. The masterpiece-gameplay amounts to what is basically Zelda in Space. Metroid Prime 4 is one of the greatest things Nintendo could do for the Wii U. Bring it.

3. Animal Crossing. This entry will be 100% replaced by New Leaf, as it is essentially the premium AC experience in terms of content. I love collecting things in games. In Pokemon, it was the titular creatures. In Metroid Prime, it was logbook scans. In Animal Crossing, it's a catalog of furniture. Talking animals? Check. Simulation? Check. A reason to play every day for thirty years? Check. A good game that my future kids will be introduced to? Check.

4. Banjo-Tooie.
5. Grand Theft Auto: San Andreas.
6. Grand Theft Auto IV.
7. Donkey Kong 64.
8. The Legend of Zelda: Skyward Sword.
9. The Legend of Zelda: The Wind Waker.
10. Metal Gear Solid 3: Snake Eater

Honorable mentions:
SimCity series.
Minecraft.
Final Fantasy VII.
Fallout 3.

It's an interesting selection since it is... only single player games, am I right?

Huh. You're mostly right. Animal Crossing, and especially Pokemon and Minecraft have some serious multiplayer aspects, but the other ones not so much. I've actually played Pokemon competitively and I do some serious breeding and trading online. I enjoy or have enjoyed a lot of multiplayer games, particularly the Smash Bros. series, Mario Kart series, Kid Icarus: Uprising, Sonic Adventure 2: Battle, Halo 2, multiplayer aspects in Assassin's Creed III, and Left 4 Dead 2, but I am primarily a single player gamer. I have a habit of turning single-player games into social experiences though. My girlfriend watches me play a lot of games, and I show a lot of single-player games to friends, most recently ZombiU. I've also thrown a StreetPass event in the past that was an Ocarina of Time 3D speed run through the first three dungeons to the Master Sword. That was a lot of fun.

This seems like a "General" or "Other Gamin" thread to me...

Interesting topic, although tough to answer, but I'll list a few of the first games that come to mind: (in no particular order)

Mass Effect Trilogy (Xbox 360) Just love the whole series, looking forward to the final DLC.
The Walking Dead (PSN Download) Not even a fan of The Walking Dead in particular, but, loved the game, story & characters.
Heavy Rain (PS3) Brilliant gaming experience & atmosphere first time through.
Star Wars KOTOR I & II ( Xbox) Loved both of these games, still waiting for a third in the series.
Mario Kart (SNES upto Wii) Liked every one in it's own way, can't wait for it to hit the Wii U.
Bioshock (Xbox 360) The original and by far the best, be interesting to see how "Infinite" turns out, it's looking promising.
Onimusha 2 (PS2) My favourite in this series, still own it today, even the graphics still look good.
Resident Evil 4 (GameCube) Still think this is the best RE game overall, just seemed to get the balance right between action & horror.
Shadow of the Colossus (PS2) Epic game in every way, still hoping to see "The Last Guardian" eventually.
GTA Vice City (PS2) Don't think they will ever better this GTA, had everything right, characters, music, setting etc.

Probably could think of loads more, but these are a few off the top of my head.

My absolute obvious ones are:
1. Super Mario Galaxy 2 (Wii)
2. Portal 2 (Xbox 360)
3. Super Mario Galaxy (Wii)
4. Simpsons Hit & Run (PS2)
5. Lego Star Wars 2 (PS2)

Then I simply cannot decide between:
-Minecraft (Xbox 360)
-Kid Icarus: Uprising (3DS)
-Mario & Luigi: Bowser's Inside Story (DS)
-Pullblox (3DS)
-Fallblox (3DS)
-Pokemon Heartgold/Soulsilver (DS)
-Pokemon Black/White (DS)
-Rhythm Heaven (DS)
-New Super Mario Bros. Wii (Wii)
-Mario Kart DS (DS)
-Halo: Reach (Xbox 360)
-Halo 4 (Xbox 360)
-Paper Mario: The Thousand Year Door (GC)
-Mario Kart 64 (N64)

I know that isn't 10, but its almost impossible to chose, because I can't judge which game I like better than another so easily because you can sometimes forget how much you enjoyed a particular game if you played it years ago. These are the game I remember most fondly, at least.

List will include Wii U won't they?

@CliffordB
Omg... How could I forget Bioshock and Resident Evil 4...
omg... no idea where to put it on my list. Argh.

1. Yoshi's Island (GBA)
2. Minecraft (PC/Mac)
3. Cave Story (3DS)
4. Team Fortress 2 (PC/Mac)
5. Super Mario Galaxy 2 (Wii)
6. Bastion (PC/Mac)
7. Ocarina of Time 3D (3DS)
8. League of Legends (PC/Mac)
9. Mario and Luigi: Bowser's Inside Story (DS)
10. Kid Icarus Uprising (3DS)

No kidding. This thread and many like it have been posted a dozen times over already. no one searches forums anymore i guess. hard to use that search function

No particular order
Legendary Axe
Phantasy Star IV
Panzeer Dragoon Saga
TLOZ WW
F14 Tomcat (C64)
Shenmue
The Record of Lodoss War
SSBM
MKDD
Residient Evil 4

I'm going to cheat as usual with 2 of these choices, though the bottom 5 change depending on my mood

1. Metroid Prime
2. Super Smash Bros. Melee
3. The Orange Box
4. Mother 3
5. Paper Mario
6. Yoshi's Island
7. Sonic Mega Collection
8. Majora's Mask
9. Super Mario Galaxy
10. Halo 2

1) Kid Icarus: Uprising
2) Fire Emblem Awakening
3) Super Smash Bros. Brawl
4) The Legend of Zelda: Skyward Sword
5) Super Mario Galaxy
6) Paper Mario Sticker Star
7) Nintendo Land
8) NightSky
9) Mario Kart 7
10) The Legend of Zelda Minish Cap

Honorable Mentions:
Super Mario Galaxy 2
Super Mario 3D Land
New Super Mario Bros. U
Little Inferno
Crimson Shroud
Animal Crossing Wild World
Professor Layton and the Curious Village