4. Elder Scrolls IV: Oblivion (PC with expansions & mods, also on 360 & PS3)
The elder scrolls games have always offered immense freedom and player choice, and Oblivion was no different. However, they also had their share of problems and the storytelling aspects weren't always as strong as perhaps they should have been. Oblivion's storytelling improved greatly upon those found in Morrowind but also added elements to make the game more immersive. Voice acting helped to bring you into the world, especially in the main quest with Patrick Stewart and Sean Bean voicing two of the main characters. No longer did you attack something without hitting it; gone was the background die roll. Attacks were now based upon your own skill rather than purely based on stats. Mini-games meant a mixture of skill as well as statistics contributed to aspects like lockpicking. And the guild quest-lines each had their own fully developed storylines that felt as if they belonged in their own seperate game.
The content of Elder scrolls games is always massive and Oblivion didn't dissappoint, but it also avoided much of the problems of generic tasks that open world games typically have. It incorporated some brilliant quests with ingenius and genuinely interesting tasks. One such example is the dark brotherhood quest which tasks you to kill five people in a locked mansion without the others knowing. Each one becomes more paranoid and scared and each has their own biases as you kill each character. The fighters guild quest which tasks you go undercover to find out the secret behind the rival guild. Or the main-line quest where you witness the destruction of Kvatch and has you entering your first Oblivion gate. The storylines (Main and guilds) were all engaging and interesting and even the one-off questlines added to the sense that this was a vibarnt and living world.
However, for me, the quality described above is only half the story. The expansions, DLC, mods and the ingenuity of the modding community are what really boost this game up to third place. Officially, the Shivering Isles added a more vibrant and bizzare world more in line with Morrowind than traditional fantasy whilst the Kinghts of the Nine DLC added an opposite questline to the Dark Brotherhood. Unofficially the OOO mod, Kumiko manor, the Achaeology guild and saddle-bags (among many others) all added great content to an already brilliant game.
Oblivion was great and some parts were better then Skyrim. The cities were better fleshed out and felt more unique. Dark brotherhood and thieves guild quest line were far superior and some of the side quests were better too. For example the one where you go inside the painting was excellent.
I didn't like most of the main quest though, I ended up skipping through all the oblivion gate worlds with /noclip /god mode. Luckily all the other quest lines more then made up for it.