I still have a lot of games I started playing and although I liked them I haven't got back to them (I fully intend to ...... one day):
Arma2 (with 6 of the add-ons)
Skyrim (I played it for about 120 hours, but have barely started the quest)
Empire: Total War
Fallout New Vegas
Grand Theft Auto: San Andreas (an old game but just bought it a month or so ago)
Medieval II: Total War (and the Kingdom version ... cant remember which one I liked now)
Mount & Blade (another old one, but fun), also "Warband" and "With Fire & Sword" although not too crazy about the last one
Napoleon: Total War
Saint's Row 2
Saint's Row the Third
Total War: Shogun 2
X3 Terran Conflict
Mass Effect 3
There are about 10 others including online games I just don't plan on getting back into. A bunch of games, and I keep going back to my modded Fallout 3. And even though I have the game of the year edition I've still only done the main quest in the original

Oddly enough I've been playing a free one on Facebook called "The Last Stand: Dead Zone" a lot. It's still in beta but fun despite some bugs. But now that missions are taking 2+ hours to come back from I'll be getting right back into Fallout 3. I should note it took me years to get into Morrowind ... so I proabably will get back to those games, just no telling when.