All Elder Scrolls games. I have no reason to finish them. I got a house, I got a badass bow, and I'd rather just make potions and eat ingredients.
Wizardry 6,7,8. Though to be fair, I can no longer play 6 because my floppy died years ago.
On a side note, Wizardry 7 was enjoyable until Gold. They should have left well enough alone.
Final Fantasy 8 and Kingdom Hearts because I spend all my time trying to get 100 whatevers to combine with 5 super ultra rares and that's more fun than beating the game and having nothing left to do.
Freelancer, X3 - Especially X3, it's much more fun to build your wealth and your galactic empire.