Since last time, more to update. (HoMM2, The Pandora Directive, MDK1, Expendable - still too be added)
HoMM3 (OC)
Eufloria
Madballs: Babo Invasion
Sanatarium
Advent Rising
The Feeble Files
Neighbours from Hell 1 & 2
Disciples 1: Sacred Lands Gold
Ghost Master
Psychonauhts
Nearly at the end of 2009 now, don't think I'll get through anything else in the remaining time.

I just beat Dragon Age.

Here are a couple I played that i really enjoyed. Although, may not be so popular. I see Weclock mentioned Dragon Age, i'm int he process of that one. Here is one that i found really nice http://www.pcgamestore.com/games/world-of-goo its called World of Goo, It was made by like 2 people or something like that. However, the music is pro, its a different type of game and the graphics are nice.
Another game that I came across that I really like but seems to be severely underrated or not as popular as it should be is this one http://www.pcgamestore.com/games/tropico-3 thats Tropico 3 if you havn't heard of it you should at least read up on it. Pretty amazing game

Resident Evil 2 is a legenday game! I had it on the GameCube and PS1 with a combined finish of 24 times. Yes, I love it that much!
This year I've been so busy with work that I've hardly finished any games at all. A few do spring to mind:
Brutal Legend
Halo 3
Fable 2
Dead Space
Resident Evil 5
Fallout 3
Arkham Asylum

Ok, couple more to add: Star Trek: Starfleet Command; Europa Universalis 3 (for those who are aware of this game, I played all 400+ years as Bohemia, and finished ranked first amongst nations.); Severance: Blade of Darkness; Starcraft; Tomb Raider Underworld; Battlefield: Bad Company; Star Wars: The Force Unleashed; Too Human.
Oh and Sam & Max Series 1 Ep 2-4

Just this minute copleted the entire (long) campaign in Battle of Britain 2 Wings of Victory!
Ninth attempt, survived the whole campaign (188 kills). SWEEEEEEET!!!!!!!!!
Also, I know it's a fairly old game now but, last week, beat the Winter Assault campaign in Warhammer 40,000 Platinum. :)

Since last time:
Kingdom Hearts: 358/2 Days
Mario & Luigi: Bowser's Inside Story
Also got some time in with AI War: Fleet Command. Gonna add it to the list once I finish a few more campaigns.

Duke Nukem: Zero Hour

Beneath a steel sky, Metal gear solid 2, Final Fantasy 4, Chrono Trigger, Indigo Prophecy, Sly 3, Paper Mario 1

You can add Braid, The Witcher, Jade Empire, and Dragon Age to my list. Going through Dragon Age again now.

Minerva: metastasis mod for Half life 2 on hard. It is ridiculously cheap at times and comes off as nearly impossible but you can beat it. I had an epic "run to the choppa!" ending where I had one hp and their was a zombie right under it. It lunged at me but I dodged it and beat the game.

Actually now that you mention it, I was going to buy it at a shop for $45 but decided not to. I bought the GBA version of FF4, and then downloaded a SNES emulator and played Chrono Trigger through that. Saved me a few dollars :P

Modern Warfare 2 on 360 on the normal settings and around 90% into Veteran. Ye Gods, that's hard.

Dragon Age and Zombie Driver.