My favorite is RollerCoasterTycoon3. What's yours?

My favorite would have to be Minecraft its an epic game about being able to build just about anything u can think of and it has various mechanics like a music box, pistons, a box that can shoot things out at you (perfect for booby-trapping your house) and a lot more, there is also tools and you can make food to heal your self and tons of other items that you can acquire only be crafting it.

Sounds interesting...

I have to go with the Sims 2. I can literally play it for hours and not get bored. Rollercoaster Tycoon is a close second, though. [=

Civilization 4. I get to build my own nation and try to "rule the world". This may involve the plain old blasting the other nations off the map, but there are other ways to win, including building the united nations and being voted in to power, showing your technology's superiority to your opponents by colonizing alpha centuri, and building culture so strong as to get even the leaders of other civilizations to want to live in your cities.  

I'd have to say Earth Eternal, which is a free MMORPG that's still in open beta, and Ultima VII. Earth Eternal just feels so inviting due to the community actually acting like functional human beings, which is a rare thing in MMOs... It's also fun to play if you enjoy grinding levels tons. Ultima VII is extremely fun. Heck, you can even get a spell that allows you to wipe out all life in the game. Except your character, that is.

Minecraft is only the way Buggy021 described as if you pay for it. That's what hurts the experience for me. I would love to pay for it, but my parents refuse to use a credit card for that stuff, and my dad doesn't need bothered just so I can use his Paypal account for that. I don't even know if I really would enjoy it for long. The free version of Minecraft is, as far as I can tell, the most basic form of the game. It's nothing but building and destroying blocks to me.

I also love the game System Shock, but have yet to get past the first level in the game. It's basically the game that Bioshock is based off of.

Awesome-Kid : Nice Picks!

My favorite is definitely League of Legends. It's a freemium game made by Riot games. It was created by the original designers of the DotA map for Warcraft 3. It's more or less a tower defense games that you play against other people.

I would say Team Fortress 2 would be second. And just because I've played them recently, Portal 2 and Dead Island for 3 and 4.

Honestly,its hard for me to pick.my main favourites are gangsters 2, dungeon keeper 2,star wars knights 1&2,and the total war series.
I cant decide which is best tbh.

Fallout 2 is starting to become another favorite of mine on the PC.

Mine would have to be either TF2 or Portal. 

One of my favorites is an older one called Urban Assault. It is really hard to explain, but basically post apocalyptic Earth where 3 factions of humans and 3 factions of aliens are all at war with each other over the planet. You are a human being who volunteered to be painfully fused into a giant flying host station. All teams have a host station (but you are the last one of your faction). In these host stations, you can create many different land vehicles and air-crafts out of pure energy that you get from taking over power stations in the area. You can assume the position of any vehicle you make, organize all your vehicles to go places or do whatever you choose. If you are in a vehicle, and you get destroyed, you simply jump to another one of your vehicles. If a host station is destroyed, all the vehicles they created are destroyed and all territories they had control over is now yours (the more space you occupy, the faster you get energy from power stations, as well as increase your energy capacity) You win the levels by destroying all enemy host stations in the level. You lose if your host station gets destroyed. As you progress, you can make better vehicles and eventually be able to make turrets. That kind of explains it. It is freaking awesome. 

You guys.... play Icy Tower. Best game ever. You have to jump to the top of the tower before you fall down. You can jump very easily and high as long as you run before you jump. The blocks get less wide as you progress. I got a top floor of 218.

Warcraft III: Frozen Throne is definitely my favorite PC game ever. From playing the actual game (which I am not very good at) to the endless number of custom games that have been made (DotA, Tower Defenses, Survival, etc.) there are enough game modes to keep you entertained for a long time.

In a close second for me would be Diablo II: Lord of Destruction. I've spent way more time than I'm willing to admit playing both of these games. haha

looks like we have some great and interesting favorite pc games.

Black and White! Its so awesome when you get to be a god! That and you get to choose to be a benevolent or malevolent one! >D

I love RuneScape and World of Warcraft.