Here's my yearly contribution to the adventure game list of 2009.
And thanks, flotsam, for making this last again

Overclocked
The Longest Journey (the first one)
Syberia (the first one)
Grim Fandango
Sherlock Holmes: The Awakened
Zork: Nemesis
Shivers 2: Harvest of Souls
Rhiannon - the curse of the four branches
Broken Sword (the first one)
Sinking Island
Post Mortem
Still Life
Keepsake
Runaway (the first one)
Escape from Monkey Island
Fahrenheit/Indigo Prophecy
Agon- The Lost Sword of Toledo
Gilbert Goodmate and the Mushroom of Phungoria
The Experiment

As you can probably see, this year, more modern games have made it to my list than last year, I think? This is because I've found that the state of adventure games really is getting better.

It's true, this list is getting more and more difficult to do, but I'm happy that new games are in it!
Thank you Flotsam, here's my games:

1 -Black Mirror
2 -Broken Sword 1
3 -Dark Fall 1
4 -Darkness within
5 -Dracula 3
6 -Gabriel Knight 1: The Sins of the Fathers
7 -Gabriel Knight 2: The Beast Within
8 -Gabriel Knight 3: Blood of the Sacred, Blood of the Damned
9 -King's Quest VII: The Princeless Bride
10 -King's Quest VIII:Mask of eternity
11 -Last Half of Darkness-Beyond the Spirits Eye
12 -Longest journey
13 -Lost Crown
14 -Rhiannon
15 -Scratches
16- Sentinel
17 -Shady Brooks
18 -Sherlock Holmes:The awakened
19 -Still Life
20 -Syberia

My list
1. Amber Journeys
2. Amerzone
3. Bad Mojo
4. Barrow Hill
5. Blackstone Chronicles
6. Dark fall 1
7. Dracula Resurrection
8. Lighthouse
9. Morpheus
10. Nibiru
11. Nightlong
12. Real Myst
13. Riven
14. Sanitarium
15. Scratches
16. Shivers 1
17. Still life
18. Syberia 1
19. Syberia 2
20. URU

Thank you Flotsam for doing this! This year has seemed to be more of a dilemna than previously but here goes:

Art of Murder 2 Hunt for the Puppeteer
Blackwell Legacy
Broken Sword 1
Colour of Murder
Culpa Innata
Diamonds in the Rough
Dracula 3
Gabriel Knight 1: Sins of the Fathers
Last Half of Darkness: Beyond the Spirit's Eye
Longest Journey
Moment of Silence
Nostradamus
Overclocked
Secret Files 2 Puritas Cordis
Shadow of Memories
Sherlock Holmes versus Jack the Ripper
So Blonde
Syberia
Tears of Betrayal
Yoomurjak's Ring

The 11th Hour
The Blackstone Chronicles
Daemonica
Dark Side of the Moon
Escape from Monkey Island
Grim Fandango
Inherent Evil
The Longest Journey: Dreamfall
Missing
Morpheus
Myst III: Exile
Neverhood
Postmortem
Riddle of Master Lu
Sanitarium
Schizm II: Mysterious Journey
Sentinel
Shivers
Voyage
The Watchmaker

Thanks Flotsam!

Here are my selections for the top games.

Ankh Reverse the Curse
Black Mirror
Broken Sword Circle of Blood
Discworld
Discworld Mortality Bytes
Dreamfall the Longest Journey
Gabriel Knight The Beast Within
Gilbert Goodmate and the Mushroom of Phungoria
Grim Fandango
Legend of Kyrandia Fables and Fiends
Longest Journey
Maniac Mansion Day of the Tentacle
Monkey Island Curse of Monkey Island
Monkey Island LeChuck's Revenge
Monkey island Secret of Monkey Island
Runaway A Road Adventuire
Sanitarium
Secret Files: Tunguska
Simon the Sorcerer
Simon the Sorcerer The Lion, The Wizard, and the Wardrobe

Well here goes, finally.

Amerzone
Aura
Barrow Hill
Beyond Atlantis
Beyond Atlantis II
Connections
Echo - The secret of the Lost Cavern
Dark Fall
Dark Fall - Lights Out
Journey to the Center of the Earth (I could listen to that music
all day)
The Lost Crown
Myst Exile
The Omega Stone
Return to Mysterious Island
Riddle of the Sphinx
Sacred Rings
Syberia
Torin's Passage

For better or worse, here's mine:

1. 80 Days
2. Azrael’s Tear
3. Broken Sword 3
4. Gabriel Knight 2
5. Gabriel Knight 3
6. Grim Fandango
7. Longest Journey
8. Moment of Silence
9. Myst 1
10, Myst 2
11. Myst 3
12. Overclocked
13. Pandora Directive
14. Rama
15. Sanitarium
16. Sentinel: Descendants in Time
17. Still Life
18. Syberia 1
19. Syberia 2
20. Vampyre Story

Checking with my previous lists, I sure am fickle.

I also see that no one agrees with me. Again.

Thank you for all your efforts with this! If you need collating help, please holler! BTW, in several cases (such as Agatha, Law & Order, Holmes) I could have listed more than one in the series, but worked to keep the list varied and to 20. Here we go:

Agatha Christie: And Then There Were None
Black Mirror, The
Broken Sword, The Circle of Blood (+ Wii & DS versions!)
Ceville
Colour of Murder, The
Diamonds In The Rough
Emerald City Confidential
Grim Fandango
Law & Order: Justice Is Served
Longest Journey, The
Lost Crown, The
Outcry
Rhiannon
Sam & Max: Season One
Secret Of Monkey Island, The
Sherlock Holmes: The Awakened (remastered version)
So Blonde
Still Life
Syberia
Vampyre Story, A

I might well have also included the Phoenix Wright series for the DS, but felt you wanted PC. Thank you....

Robertson

Well here it is whittled down to the best of my abilities. This is a list (-about another 20) of my all time favorite adventure games. I would recommend them to anyone and this is my list and I'm sticking to it.

Art of Murder
Belief and Betrayal
Broken Sword Circle of Blood
Chronicles of Mystery
Conspiricies
Gabriel knight: The Beast Within
Kings Quest II
Kings Quest VI
Legend of Kyrandia Book 2
Longest journey
Moment of Silence
Nibiru
Pandora Directive
Phantasmagoria
Ripley's Believe it or Not
Ripper
Runaway
Secret Files Tunguska
Still Lilfe
Syberia

After careful consideration:

Amerzone
Black Dahlia
Byzantine: The Betrayal
Dark Fall I
Experiment
Feeble Files
Ghost Master
Grim Fandango
Last Express
Lost Crown
Moment Of Silence
Overclocked
Sanitarium
Syberia I
Syberia II
Tex Murphy: Overseer
Tex Murphy: Pandora Directive
Tex Murphy: Under A Killing Moon
Yoomurjak's Ring

here is my list of the year.

Agatha Christie - Evil Under The Sun
Anacapri
Art of Murder - Hunt for the Puppeteer
Believe and Betrayal
Black Mirror
Carol Reed - Hope, Springs, Eternal
Darkfall 2
Diamonds in the Rough
Dracula 3 - Path of the Dragon
Keepsake
Lost Crown
Longest Journey
Rhiannon, the curse of the four branches
Riven
Secret Files Tunguska
Sherlock Holmes versus Jack the Ripper
Still Life
Syberia 1
Syberia 2
Yoomurjak's Ring

Hi all,
My apologies - real life intervened!
Its early days but Syberia already leads the way. Chasing hard are Syberia 2, Still Life and Black Mirror.
New games that have started well include Sherlock v Jack the Ripper and Rhiannon.
Nearly 200 games mentioned already and over 30 that weren't mentioned last year (including a couple I have never heard of).
Keep em coming

Here is my list .

1. Agatha Christie And Then There Were None
2. Agatha Christie Evil Under Sun
3. Art of Murder FBI
4. Art of Murder Hunt for the Puppeteer
5. Barrow Hill
6. Black Mirror
7. Chronicles of Mystery The Scorpio Ritual
8. Darkfall The Journal
9. Darkfall Lights Out
10. Dracula Origin
11. NiBiRu
12. Overlocked
13. Secret Files Puritas Cordis
14. Secret Files Tunguska
15. Sherlock Holmes The Awakened
16. Sherlock Holmes Jack the Ripper
17. Sinking Island
18. Still Life
19. Syberia 1
20. Syberia 2

There are some games I haven't played yet which may have made it on the list instead of others but that will be for the next time. Thanks Flotsam for making the list .

Oh dear! Only 20?
OK, I'll try.

1. Agatha Christie And Then There Were None
2. Agatha Christie: Murder on the Oriental Express
3. Beyond Atlantis
4. Carol Reed: East Side Story
5. Carol Reed: Remedy
6. Cleopatra: Riddle of the Tomb
7. 11th Hour
8. Escape from Monkey Island
9. Indiana Jones and the Fate of Atlantis
10. King's Quest IV
11. Longest Journey
12. Myst
13. Nancy Drew: Ghost Dogs of Moon Lake
14. Nancy Drew: Secret at Shadow Ranch
15. Omega Stone
16. Rhem
17. Riddle of the Sphinx
18. Riven
19. Sherlock Holmes: The Case of the Silver Earring
20. Vulcan episode 1 (ValhallaClassics)