I sort of forgot about Viva Pinata: Trouble In Paradise, anyone who has played this or VP knows that of which I speak...

Harpoon was a big "user" of my time way back when. Today? It's this awesome Mount & Blade Warband. Completely loving this game.

Morrowind, of course. Weirdly it was the XBox version I played first (at a friend's place), but that was a dog so I got it on our PC (GeForce 2, good times). I've got Morrowind and about two hundred mods installed even now, but I daren't play it because I know I won't be able to stop any time soon. No doubt I have sunk more hours into Morrowind than any other game ever.

The Legend of Zelda: Majora's Mask is another one. Have to love the world; it's like a surreal painting. It's also unique in that my mom approved of my playing it, although I'm not entirely sure why.

Also, the Pokémon games on various Game Boys and, to a lesser extent, the Nintendo 64. Think what you will of Pokémon - I do - but some of the games are genuinely good, others brilliant. There, I said it first. You can come out of you Pokémon closets now.

Games that I wouldn't count as life stealers but are still pretty important when it comes to my earlier years include Paper Mario, Jet Force Gemini, F-Zero GX, Metroid Prime, Super Smash Bros. Melee and Goldeneye.

Master of Orion 2. The only game which I've been playing on and off for over a decade and a half.

Pizza Tycoon comes a close second though.

I've spent some absurd amount of time on Warcraft III. But not because it was a good game, in fact I thought it sucked so much I felt compelled to mod the shit out of it for years.
In the end I didn't finish anything worth mentioning (nor did most of the modding community) but at least it has been a lot more fun than playing the base game.

In my case it's the Anstoss- and the mother of all time eaters - the Civilization-series.

Diablo 2, WarCraft series, WoW, Counter Strike, Heroes 3, Red Alert 2.

Powermonger (vote for it!) and Everquest

Some of the games I've spent the most time with are:
Civilization 1+2
Dungeon Keeper
Moonstone
Heroes of Might and Magic II
Diablo II
Classic LucasArts adventure games
Transport Tycoon
Minecraft

Baldur's Gate, it still is.

earlier in my life: Age of Empires I and II, which were two of my first games, and Battlefield 1942 in single player campaign mode.