Elder Scrolls games, Mass Effect games, Deus Ex Human Revolution and Dishonored. These are my favorite closely followed by Dragon Age Origins.

Awesome choices everyone, thanks for your replies!! :)

Jak & Daxter: The Precursor Legacy, for so many reasons.

Shadow Man

A masterpiece!

Heavy on the voodoo theme, it is a dark and twisted game that gets under the player's skin. The best way to describe is Legend of Zelda for adults due to the mature themes. Plus it has a fantastic yet disturbing soundtrack. Asylum: Playrooms is a disturbing track that the player can never forget once they have heard it.

GTA IV. V will be #1 soon. No wait, V is already my most favorite game. ;)

You have already played the new Tomb Raider, didn't you? And you didn't like it:o I see your rating, lol. 

Well I haven't played the most recent titles but I would recommand Batman Arkham City and of course Fallout New Vegas, incredible game IMO, way better that Fallout3.

@SoNin360 yeah GTA SA is certainly one of the best games ever made. Well Fallout3 was good but I liked FalloutNV much more.

In no order: Chrono Trigger, Ocarina of Time, Metal Gear Solid 3, Skyrim, Red Dead Redemption

Shadow of the Colossus is #1, followed by (in no particular order) Red Dead Redemption, Batman Arkham City, Legend of Zelda, and Uncharted 2

The Dead Space series, The Bioshock series, Silent Hill, Silent Hill 2, those are some of my favorites

Chrono Cross. The art and music is breathtaking, the story is beautiful and eerie at the same time, dimension-hopping is awesome, and it has my favorite turn-based battle system.

I have a few but my all time favorite (of course :P) is ocarina of time.

For current generation I'd have to say Heavy Rain. As for old school games, I'd go with the Megaman X series.

Dragon age:origins is my favorite game.

Of all time? Gotta go with Fallout 3 and GTA: San Andreas.

WHOA, you liked the newest God of War? Wow. :o

Haha...I have too many. So I'll just go with the 3 games I've rated a perfect ten: Xenosaga Ep 3, Persona 3, Tekken 3 (I never noticed before, but I seem to really like third installments!)

I think that will be Tie Fighter: Collector Edition.

Of all time: Final Fantasy Tactics

Dark Souls, Metal Gear Solid 4, Ocarina of Time , Skyrim.

Fallout New Vegas is my all time favorite. The Fallout and Thief series are my all time top two favorites. Then there is Bioshock, which is close up there as well.

Dark Souls.

That's a tricky question. Bomberman on the SNES is usually my stock answer for that question but Shadow of the Colossus is another great game (you can get that on PS3 too). I loved the Mass Effect series and have just finished Bioshock 2 and Spec Ops: The Line so they are well worth a punt.

It's an ever changing answer, but if I had to look back at games I really enjoyed at the time I would have to say NFS Shift is up near the top!

I have a lot of favorite games, but perhaps one game that's edging for the top uppermost spot is Castlevania: Symphony of the Night.

The World Ends With You (DS)

Hmmm, can't really pick just one, but if I had to it would be Dark Souls. The experience I had the first time I played Fallout 3 has not yet been matched. I would put Dark Souls ahead of it simply because I don't think I will ever get tired of that game while I don't have much desire to return to Fallout 3. I do have Fire Emblem Awakening and Ni No Kuni unopened ready for me which could be some of my favorites based on what I have heard, but I have to get through a couple of other games first. In short, I guess I really like addictive games.

I'm not sure I can name just one, here are some I like at the moment

PS3

Okami HD, THPS HD, Eternal Sonata, Rayman Origins, Dynasty Warriors Gundam, GTAIV, God of War series, Ratchet & Clank Tools of Destruction and Ratchet & Clank Up Your Arsenal, NBA Jam, Tokyo Jungle, Mass Effect, Shoot Many Robots, Sonic the Hedgehog series, Rocket Night, Blade Kitten, The Simpsons Arcade Game, Assassin's Creed series, Infamous,  Champion Jockey G1 Jockey & Gallop Racer, Blades of Time, Sly Cooper series,  FFXIII, FFXIII-2, Red Dead Redemption,  Borderlands, Tron Evolution, Legend of the Guardians Owls of Ga'hoole, Batman Arkham City, Metal Gear Solid series, Prince of Persia Trilogy,  El Shaddai, Bayonetta, Bioshock,  The Cursed Crusade, Spider-Man the edge of time, Brutal Legend, Aliens vs Predator, Singularity, Tom Clancy's Hawx, Dead Rising 2, Split/Second, Majin and the Forsaken Kingdom, Enslaved Odyssey to the West,  Dragon Age 2,, CODWAW, and Dark Sector.

PS2/PS1

Okami, Legend of Kay, Kingdom Hearts 1 &2, GTA Trilogy, Dragon Rage, Savage Skies,,Spyro the Dragon and Crash Bandicoot, Ecco the Dolphin defender of the future

Xbox 360/Xbox

Dust An Elysian Tail, Fable III, Halo 3, Gears of War, Darksiders, Dark Messiah, Tales of Vesperia,Kameo Elements of Power, Phantom Dust

Nintendo Wii/GCN

Legend of Spyro Trilogy, Super Mario Galaxy, SSBB, No More Heroes, Tales of Symphonia, Animal Crossing, Donkey Kong Country Returns,Second Sight, Legend of Zelda Series, Pokémon series, Viewtiful Joe, Resident Evil 4, Billy Hatcher and the Giant Egg, Sonic the Hedgehog series, Baten Kaitos, Lost Kingdoms, Luigi's Mansion, Paper Mario, Starfox Adventures, Metroid Prime, Big Mutha Truckas, Tony Hawk's Underground,F-Zero GX, Custom Robo, MVP Baseball 2004, Tiger Woods PGA Tour 2005, NHL 2005, Soul Calibur 2, Star Wars Clone Wars and Rouge Leader Rouge Squadron 2

Nintendo 3DS/DS/GBA/GBC/GB

Resident Evil Revelations, Kingdom Hearts, LOZ OOT, Pokémon series,Okamiden, Castlevnia Dawn of Sorrow, LOZ phantom hourglass, loz link to the past, link's awakening,Pokemon Mystery Dungeon series, Sonic Rush, Spyro series, Super Mario Land, LOZ oracle of seasons and ages

Sega Genesis/SNES/N64/NES/Sega CD

Yoshi's Island, LOZ LTTP, Sonic CD, Sonic 1-3, Sparkster, Cool Spot, Pokémon Stadium 1 & 2, THPS, SSB, LOZMM, The Lion King, Aladdin, Ecco the Dolphin, Izzy's Quest for the Olympics, Beyond Oasis, Jurassic Park rampage edition, Mickey Mouse timeless adventures, MS. pac-man, Paperboy, Pocahantas, TMNT, Hyperstone heist, Tiny Toon adventures buster's hidden treasure, Bugs bunny in double trouble, Taz in Mars, Vectorman, X-Men 2, Seperation Anxiety, Super Mario Bros, Duckhunt.

Maybe I listed too many, well have fun. Then again I did say I had a lot of favorite titles so....Not sure if I forgot any.

The new Tomb Raider is good. But I got way to many favorites: BioShock, Assassin's Creed, Halo, Call of Duty, Gears of War, Elder Scrolls, The Witcher, and Far Cry 3. The Walking Dead! All awesome stuff.

One? Ocarina of time. Two? Halo. Three? Anything Elder Scrolls.

Well, for X360 and PS3 game I'm "Very" fond of Mass Effect.

But I also Liked Halo. Okami is starting to be my favorite.

but if you ask if only one, then my answer is Mass Effect.(series)

It's always changing for me. Of all time: probably Streets of Rage 2. Right now: Fear Effect.

Baldurs Gate 2 is my favorite

Some other top games would be 

Fallout 2, Ring of Red, Fire Emblem 4, Planescape Torment, Ogre Battles 64, Persona 4 Golden, Final Fantasy 6, Final Fantasy 9, Shin Megami Tensei Nocturne, Paper Mario, Valkyria Chronicles, Yakuza 3, Yakuza 4, Suikoden, Suikoden 2, The Walking Dead, Mark of the Ninja, Paper Mario, Front Mission 3, Batman Arkham Asylum, Batman Arkham City, Ghost Recon Advanced Warfighter, Marvel Ultimate Alliance, Mass Effect 2, Saints Row 2, Resident Evil 4, Tales of Vesperia, The Witcher, The Witcher 2, Splinter Cell 3, Star Wars Knights of the Old Republic, Bushido Blade 2, Blaz Blue, Jagged Alliance 2, Mega Man X 1-3, and Bastion.

Damn. One? There are just way too many to name. But, here goes:

PC:

Unreal Tournament GOTY, UT2004 (best in series), Guilty Gear X2 Reload, GG Isuka, Deus Ex, Retro City Rampage, Street Fighter Alpha 2, System Shock 2, Divinity II Developer's Cut (heir to Oblivion's throne), Fallout 3, Oblivion, The Orange Box, Left 4 Dead 2, KOTOR, Torchlight, Anachronox, Ys The Oath in Felghana, Project Black Sun (tough as nails, but worth owning), Gorky 17, Rayman 3 Hoodlum Havok, Prince of Persia The 2 Thrones, Gunstar Heroes, Phantasy Star IV, Streets of Rage 3, Sonic 3 & Knuckles.

DS Lite/GBA:

Chrono Trigger, Final Fantasy VI, Lunar Knights, Street Fighter Alpha 3, Castlevania Portrait of Ruin, Castlevania Aria of Sorrow, Mega Man Zero Collection, The World Ends with You, Scurge Hive (both DS and GBA), Super Mario World, Gundam Seed, Rock n Roll Racing, Boktai 2, Gunstar Super Heroes, Summon Night Swordcraft story 2.

Not neccesarily in that order, and I probably left a few out. But there's my 'short' list on my preffered platforms, PC and DS Lite/GBA.