Presently? Dark Souls. I fupping hate that game, but good GODS it's addicting. I've raged at that game far more than any other that I've ever played, even rage-uninstalled it something like 20 times, but something keeps calling me back to the rage-fest that is Lordran. I recently started playing it again, starting a new character, and focused on playing solely online. (I was afraid of invasions and the like before because I knew nearly nothing about the game. Now that I know a whole heap more about how humanity and being Hollowed works, I spend most of my time human with 20k+ souls on me, almost at all times. Also, lag-stabbing like a boss.) I went from around 30 hours on my "main" file, (I used a trainer and played offline with that one), to almost 70 on my new one, all in less than a month. Whoof. Quite a time sink, this game.
Before that, though, I was trying to earn my real-life fortune in Entropia Universe. I spent something around 50 hours farming vibrant sweat from these nasty buggers near the starting area on Calypso, just to make the equivalent of $10. And then I spent all that on a spaceship that almost instantly ran out of fuel upon leaving orbit, and then got shot out of the sky by pirates. 50 hours of work, gone in less than 10 seconds. Rage-uninstalled that shit, post-haste.
But the main game that ate up a ton of my time is Kingdom Hearts II: Final Mix+. I spent over 100 hours farming for the Ultima Weapon, perfecting my fight against Sephiroth, filling up my Journal, and then getting my ass kicked to next Friday by the Lingering Will. Still haven't gotten 100% on the Journal, and I've resigned myself to the fact that I never will. I've instead decided to get 100% on my Trinity Archives in Birth by Sleep while I take a break from Dark Souls. I recently just lost over 50 humanity and 100k souls in Anor Londo due to my own stupidity. I think I need a break from that game for a while, else my computer might take a break from me, if you catch my drift... >_> lmao