I rarely complete a game. At least not in the first try. Typically i complete like 60%, start on another one, restart the previous one to remind myself of the story and complete it. Like my strategy

I try to complete them

I complete BAD games...

I have 1000 gamerpoints in:

Bullet Witch

Ninety-Nine Nights

and last but not least...

King Kong.

The only games that I have/had 1000 gamerscore are pretty much just EA games which are usually easy(Madden 06, 07 on my old account, 08, and NFS:MW). On my old account I also had all but one achievement on Gears of war, I think it was the one for hosting 50 matches or something. I only need to beat one level of halo on legendary to get the heroic and legendary achievements, but I' m too lazy to bother.

I finish most of my games before playing another usually be playing 3 or 4 games at one time.
One i have finished then if the game is worth another shot on a harder difficulty and has some good replay value i will play it again aiming to get everything if i missed something on the first run.

I don' t play that many games like I used to. but I try to finish my games. right now I haven' t beat lost odyssey I put it away. I' m kind of stuck. I' m waiting for the release of codebreaker so I can cheat in lost odyssey. I just finish devil may cry 4 like about 2 weeks ago.

i think i am a good player but only don't like strategy games very much and i all the time finish the games which i start but i can't play the last 2 years' games since my computer is old..so here is my %100 finished game list(total: 119):

Atlantis III(Full)
Atlantis The Lost Tales(Full)
Beyond Good&Evil (Full)
Blade Runner(Full)
Blood Rayne(Full)
Broken Sword I(Full)
Broken Sword II(Full)
Broken Sword III(Full)
Broken Sword IV(Full)
Brothers In Arms Earned In Blood(Full)
Brothers In Arms(Full)
Call of Cthulhu(Full)
Call of Duty 1(Full)
Call of Duty 2(Full)
Call of Duty United Offensive(Full)
Chronicles of Riddick(Full)
Condemned - Criminal Origins(Full)
Conflict Desert Storm 2(Full)
Counter Strike Condition Zero(Full)
Crimson Skies(Full)
Culpa Innata(Full)
Dark Fall(Full)
Delta Force Black Hawk Down(Full)
Delta Force Task Force Dagger(Full)
Deus Ex 1(Full)
Deus Ex 2(Full)
Doom 3(Full)
Dracula Origin(Full)
Dreamfall(Full)
Dungeon Siege 2(Only Main Missions)
Enter the Matrix(Full)
F.E.A.R.(Full)
Fahrenheit 911(Full)
FarCry(Full)
Flatout 2(Full)
Freedom Fighters(Full)
Freelancer (Full)
Getting Up(Full)
Ghost Recon Advanced Warfighter (Full)
GTA 3(Main Missions)
GTA San Andreas (Full)
GTA Vice City (Full)
GUN(Full)
Half Life 1(Full)
Half Life 2 Episode One(Full)
Half Life 2(Full)
Harry Potter 2(Full)
Hitman Blood Money(Full)
Homeworld (Full)
Independence War 2(Full)
Indiana Jones And The Emperor's Tomb(Full)
James Bond Nightfire(Full)
John Saul's Blackstone Chronicles (Full)
King Kong(Full)
Lucky Luke(Full)
Mafia(Full)
Max Payne 1(Full)
Max Payne 2(Full)
Medal of Honor Allied Assault(Full)
Monkey Island 1(Full)
Monkey Island 2(Full)
Monkey Island 3(Full)
Monkey Island 4(Full)
Moto GP 3(Full)
Need for Speed Most Wanted(Full)
Need for Speed Underground 2(Full)
Need for Speed Underground (Full)
No One Lives Forever 1(Full)
No One Lives Forever 2(Full)
Operation Flashpoint (Full)
Post Mortem(Full)
Prince of Persia Sands of Time(Full)
Psi Ops Mindgate Conspiracy(Full)
Psychonauts(Full)
Quake 4(Full)
Rainbow Six 1(Full)
Rainbow Six Eagle Watch(Full)
Rainbow Six Rogue Spear(Full)
Red Faction 2(Full)
Resident Evil 4(Full)
Return to Castle Wolfenstein (Full)
Return to Mysterious Island(Full)
Runaway 1(Full)
Runaway 2(Full)
Sam & Max Episode 101 Culture Shock(Full)
Sam & Max Episode 102 Situation Comedy(Full)
Sam & Max Episode 103 The mole, the Mob and the Meatball(Full)
Sam & Max Episode 104 Abe Lincoln Must Die!(Full)
Sam & Max Episode 105 Reality 2.0(Full)
Sam & Max Episode 106 Bright Side of the Moon(Full)
Sam & Max Episode 201 Ice Station Santa(Full)
Sam & Max Episode 202 Moai Better Blues(Full)
Sam & Max Episode 203 Night of the Raving Dead(Full)
Sam & Max Episode 204 Chariots of the Dogs(Full)
Sam & Max Episode 205 What's New, Beelzebub (Full)
Sanitarium (Full)
Scarface(Full)
Scrapland(Full)
Second Sight(Full)
Spider Man(Full)
Splinter Cell Chaos Theory(Full)
Splinter Cell Pandora Tomorrow (Full)
Splinter Cell(Full)
Star Wars Republic Commando (Full)
Stillife(Full)
SWAT 4(Full)
Syberia 2(Full)
Taxi Racer London 2(Full)
The Black Mirror(Full)
The Godfather (Full)
The White Chamber(Full)
Thief 3 Deadly Shadows(Full)
Tomb Raider 1(Full)
Tomb Raider 2(Full)
Tomb Raider 6(Full)
Tomb Raider 7(Full)
Tracmania Sunrise Extreme(Full)
Ultimate Spider-Man (Full)
XIII(Full)

I rarely finish games (unless I'm reviewing them, of course) but I generally get past the halfway mark.

Variation on the theme: what's your ideal length for a single-player storyline? 6-8 hours does it for me in an action game/FPS, while RPGs need to be a good 20 hours minimum.

I try to finish my games unless I get bored of them.  Oblivion is the big exception, I played that for 120+ hours and never completed the main quest.  I managed to lose Jauffrey somewhere in the wilderness and couldn't open cloud temple.

I like my story line in games to be at least 12 hours, too many games are too short these days.  RPG should definitely have more time, Mass Effect nailed it on the short side, Fallout 3 was a bit too short.

Iad umboros

Fallout 3 was a bit too short.

You did it wrong.

Rubbish, the ending just jumped me!  Didn't get any of the expansions though, might buy GOTY edition as I've got back into Oblivion thanks to the Shivering Isles.

I beat Halo 3 on normal.