Amazing world.....full of mountains, forests, secret caves & so on

Compelling side missions with amazing stories

Fantastic "lore"

Tons of extra content apart from main quest

Easy to pick & play

Great magic animations

Great minigames

Most importantly it was FUN FUN FUN FUN......just so much FUN

To date its the only RPG that beats a mainline Final Fantasy released in the same year (FF12).

ITs the best WRPG for me.....but then again I have only really played 4 other WRPGS -- KOTOR 1, KOTOR 2, Fallout 3 & Dragon Age Origins

But oblivion kicks Fallout 3 & DA:O's ass

It beats KOTOR 2 by a lot

It beats KOTOR 1 by an inch.

Oblivion FTW!

For me
1.Fallout 2
2.Kotor
3.Fallout 1

First, because it's open world and not linear. The world is well balanced between random and hand-placed stuff so it makes it interesting to explore and spend time in. It's inhabitans are independent instead of scripted. The quests are well written and varied. It's got addictive core RPG gameplay mechanics (leveling, loot). The alchemy is complex and fun. Combat is raw and feels right.

The design of the world and it's lore is fantastic. It feels alive, natural, logical and never artificial. It looks beautiful. It's got very lovable characters and dialogue. The overall mentality and moral in the game is very appealing.

Best WRPGs that I have played is....
Mass effect 2.
Runner ups: Mass Effect and Oblivion.

KOTOR MASS EFFECT 2 & FABLE2

1. The Elder Scrolls IV: Oblivion

Exploring New Worlds, learning about hidden secrets and Organisations... i dont give a damn about the Storyline, because every damn town was an adventure itself.

2. Gothic (1)

This Game was Badass. it was kinda Open World, even if it was not nearly as Big as its Rival Morriwind, it was damn atmospheric, and pretty Badass.. i mean, exploring a World, ONLY filled with Bandits, thiefs and Murderers that are trying to Survive their Exile in this damn part of the World.. awesome. :3

3. DA:Origins / Fallout 3

DA's Storytelling was Awesome, and the Lore, the Scenery, it felt just great. the only bad thing is, that the Combat-Skills werent as deep as they looked @ the beginning, at least compared to similar Games. // Fallout's Setting isnt my Type, but even so, this Game caught me until i had the Platinum Trophy.

Gothic I+II, Vampire tM: Redemption/Bloodlines, KotOR

If I had to choose: Gothic II.

Neverwinter Nights 2

And Shandra Jerro's death is a fucking shame plot,I mean why the f*ck let her die.

Knights of the Old Republic 2

Yes it is.

I'm very much new to the genre. I've only really played Mass Effect 1/2, Dragon Age: Origins, World of Warcraft (I suppose this qualifies?) and KOTOR 2. I thought all of them were fantastic, but would probably lean toward WoW - if it counts - or Dragon Age: Origins.

I've played a few others years ago, but didn't really give them much of a chance. I'd like to try them again.

Edit: I'd forgotten about Diablo I/II. Both were increble games.