Do have a game or games that you have had for years but you find that at least every year or so you reinstall it and play though it again?

For me, my repeat offenders have been MOO2, the Imperialism series and Hearts of Iron 2. I bought each of these games when they are were new and over and over again I find myself playing through them again.

EASY:
AOE 1 and 2
Commandos BEL

Morrowind. Definitely Morrowind. I was playing it on my first actually powerful computer. I was playing it about 30 minutes ago.

Also, Dawn of War games.

Original Tropico games, nothing wrong with the newer ones either. Just got a soft spot for the two first Tropico games.
Also probably VVVVVV would be on that list.

Arcanum for sure. I have had it installed on every computer I used since I got it in 2001.

Morrowind as well, like Fenixp, though not as much as with Arcanum (since Arcanum doesn't really require a whole butt load of effort to install, and then install tons of mods into like how I play Morrowind).

Other than that not really consistently. But I often get the feeling of wanting to play some type of RTS, or strategy game and so I'll either pull out an old one or find a newer one that is good (most recently I bought Galactic Civilizations 2 during the Steam sale).

Morrowind, that game is great :)

Hahaha
After I finished Homeworld I thought, "Great game! I'm never going to do that again!!!" Between the junk yard dog and the giant meteor, I pulled out enough hair playing it just the one time. Still, a true classic!

Minecraft, obviously :)

Beyond that...Civilisation (4, now, though for a long while I played 3), but that's more in the nature of the game than anything else.

Oblivion technically, but only because I keep coming back for a day or two at a time to see if it really is as bad as I remember (and also to try and get through the story so that I can actually know what happens. Otherwise I can't roleplay my character's descendent in Skyrim)!

Now, Morrowind would make this list, right at the top, but I actually only got it quite recently, and so have only played it through once. Now I'm letting it fade a little in my mind before I come back to it, so so far it doesn't make the list. I think it will in a few years, though...

Is Morrowind that much different that Oblivion? I was in another thread talking about how I liked Oblivion to a degree but there was a lot they could have done better, so someone immediatly recommended Morrowind. It's currently in a mail truck on its way to me.

Depends, what did you like and what did you dislike about Oblivion?

Well for starters the specs. I could run it but not really well and the dropping framerate when I started hitting spires got kind of annoying. Also, the vagarity and setup of the country side; I'd spend all day going into mines and caverns and visiting shrines and killing bandits but I never felt like I was getting anywhere or accomplishing anything. I like an open free form world but untill I started hitting walktrhoughs I have to clear 5 or 6 dungeons just to get to the one I was looking for in order to find the object I wanted. Lastly that Fu&%ing super powerfull ring that slides into the ocean making you spend 2 hours blindly groping around for it if for no other reason than to be able to tell everyone in the Oblivion forums that you actually found it.

As usual, I'm destroying Zookies thread with my tangents. Ooops!

I always have Morrowind installed and dip into it pretty regularly.

I replay Bioshock, Mirror's Edge, Sam and Max Hit the Road, Under a Killing Moon and the Deus Ex and Thief games all the time, about once a year I guess. There are probably a few others too I am forgetting.

I often load a Monkey Island game up for a little bit just to cheer myself up.

Mine is Psychonauts. Not exactly sure why but its fun to just pick up every now and then.

Planescape: Torment
Sam & Max (The Telltale bunch, only the first two seasons)
Monkey Island 1 and 2!

aaand... I don't even know, I try to keep it fresh in the game department. Mostly trying something new, I'm really not the replaying type, unless the game is quite big like Deus Ex or Morrowind or Fallout, but I can hardly call them games that I keep coming back to, because I only have just 1 or 2 extra replays in mind for them.