what are some games that you play through, and uninstall, but they never really stay off your computer for long? Games you keep going back to like a scorned lover? SHARE PLEASE!
Mine would be...
Diablo II:
every once in a while I just get in the mood for some mindless RPG, and no other fits the bill like Diablo II. It's never uninstalled from my computer for very long
Syberia:
like clockwork, as soon as I've forgotten how to play through this, I get in the mood to play it again. And it's like playing it for the first time (though a few things do come back to me now and then). I just love this game and it's moody/creepy atmosphere
Neverwinter Nights:
its the campaign builder that makes me come back to it. I get ideas in my head, build glorious maps/storylines, realize I don't know how to put it on a server or anything, realize no one will ever play it. Delete, try to play the single player campaign (get bored FAST), play a few rp/action servers, uninstall. Lather, rinse, repeat!
Sims 2:
I don't even LIKE this game. But someone gave me a copy. I do, however, LOVE building houses/stores/etc, and furnishing them. But when it comes time to play, I get bored FAST. The building joy wears off soon, and the game is once again uninstalled
Black & White:
with every reinstall, I tell myself 'if I just play past the first 2 levels, it will be better". But no.
Great concept of a game, completely ruined by the needless pets. Here I am trying to build a civilization and get them to worship me... must I really have to break away every so often to spank a giant turtle because he's eating villagers and pooping all over my precious town?
(apologies if there is a topic like this already. I checked a few pages back though)

Most of the games you can play on ScummVM are the ones I keep going back to, easy to pick up & play and top quality games.
RPGs normally command most of my replay attention, I've only got one achievement left in Mass Effect and thats the 'complete on insanity' so you can imagine how much I've played that game.
Civilization games are also a major drain on my time but that's hardly unusual, seems to happen to everyone

Xcom - I simply cannot ever get enough of this game. About once a year it finds it's way back in to my play rotation.
Age of Wonders : Shadow Magic - It isn't Masters of Magic, but it's the closest thing there's been since MoM...if Stardock's upcoming Elemental is as good as it looks now, my addiction to AoW : SM may come to a close.
Knights of Honor - Think of it as the bizarro version of Total War...the tactical set up is pretty cheezy (though it works), but the strategic portion of the game is much better.
Europa Universalis 2 - This one has spent a lifetime on various hard drives of my various computers. Probably about to be 'passed on' to a friend, though, since I got the Complete edition of EU3 for Christmas.

Quake - For a variety of reasons. For one, this game really never gets old. Literally. The Quake engine is still under very heavy development and every time you come back, you'll see some new effects. Look at Nexuiz, which is built on DarkPlaces, a very popular Quake1 engine. And it's not just the engine: You can get texture sets that will put most "modern" games to shame. You can get new levels, gameplay mods and what not. Snowboard? Racing? Flight Simulator? Chess? Quake can do it all! The standard gameplay is very simple, but if you like very linear shooters like Prey, you'll love Quake.

Dungeon Keeper
I just love this game, and it's so relaxing to get back into it after a long absence.
Theme Hospital
Another Bullfrog game oddly enough. From the brilliant PA announcements to the crazy ailments and the fantastic sprites - this is possibly my favorite PC game of all time.
Alpha Centauri
This was one of the few PC games I had for a long time that did not require the CD to be in the drive to play, so I would boot it up from time to time when I was too lazy to search through my piles of CDs.
Grim Fandango
My favoritest of the Lucasarts games. A pure delight.
Man.. this list could go on for days, but those are the ones that leap to mind as my most played.

Dungeon Keeper
Slapping Imps, that's all you need to know.
Sim Tower
Just managing a tower, trying to get more efficient each time.

Starlancer: Like a good movie, I come back for those excellent cinematic moments time and again.
Galactic Civilizations II: "THIS time I'll play a giagantic map through to the end!" Never do, and the game does eventually get uninstalled. But always sneaks back on. I feel it lacks something significant to make it stay.
Total War Games: The only time one leaves my hard drive is when another arrives.
Audiosurf: I can't express my love for this game enough. Some thrashing metal + Ninja mono + iron mode = Exhilirating Glee.
If I spent more time considering I could list more. But yeah, as someone else said, these came to mind

Freespace 1 and 2.
Baldur's Gate 1 and 2.
Counter Strike (I hate it, but still love it)
Battlefield 2
I've tried Starlancer a few times but i keep getting killed by THE GODDAMN BEAM WEAPON THAT KILLS YOU IN ONE SHOT AND IS ANNOYING AS HELL TO AVOID. so i stop after it gets me like 5 times in a row.
Fallout 1 and 2

ah! I've always wanted to play that. I only ever tried the demo (loved it) but I can't finda copy anywhere

Diablo II, Baldur's Gate for my RPG fixes... I just finished Fallout 1+2 for the first time, but I foresee added that to this list in the future.
Halo 3, Half-life 2 for FPS.
Oh, and World of Warcraft, over and over. Will cancel for 6 months or so, play for 3... pretty much since launch..

Sim City 3000
It isn't a ugly as 2000 and runs smoother and is more fun as 4
Morrowind
Install it at least once a year. Play it, run into a bug, get angry with it and uninstalls it again.
RA2
It's fun, tender on the pc and has still the real C&C install procedure.

forgot about Morrowind... I do go back to it a lot, definitely more than Oblivion. Although Oblivion + mods isn't so bad.
I've never really run into that many bugs though,at least none that impeded my progress.

As of right now, I just dug up my copy of Vampire the Masquerade Bloodlines. I am playing as a Malkavian right now and let me tell you it is very,,....interesting to say the least.
Sometimes I boot up Arcanum or Temple of Elemental Evil. Yes, I love me some Troika games; too bad they are no longer around as a company.

Sin Episodes, Breakout, and Super Mario bros.
Tetris Attack, Pokemon, and more..

hmm locklock was again quicker, i will never become real spammer.....
For me it is Baldurs gate and fallout series (no, F3 is NOT part of the fallout) nothing else, those was my first BIG RPG's in my life and it will stay in my heart forever