I'll keep an updated list here of the games I currently plan on playing but haven't found the time for.
Fire Emblem 4 - I'm really already quite far into this, it just takes me a while to play as I'm the kind of person that hates to lose units and can restart a mission just to save someone. With how easily some characters can die and how long the missions are in this one, it can take me a while to play a single map.
Half Life 2: Episode 2 - I can't believe I still haven't played this one, I just need to find the time to sit down and play through it.
Trine 2 - Most of the way through this one as well, just need to finish it up.
Botanicula - A cute point and click puzzle game from the makers of Machinarium. Had this for a while, just need to actually play through it.
Fallout - Picked this up for free a while back when GoG had a promotion going for it. Like the other games on this list, I just need to find the time to play it.
If you have any suggestions for a game, feel free to drop me a comment and I'll check it out. Keep in mind that I only have a laptop and a DS to play on right now, so I can't play anything top of the line right now.