Games like Fallout/Elder Scrolls?

Just Cause 2

Arcanum: Of Steamworks and Magick Obscura

I'm not sure about it but the gameplay of Numen:Contest of heroes looks a bit similar.You can get it from the latest Bundlestars Bundle.

Baldurs Gate 1&2, Neverwinter Nights 1&2, Icewind Dale 1&2, Planscape Torment all these are classic and must play for true RPG gamer

Maybe Divine Divinity and Divinity 2

Games I have played and feel are like Fallout/Elder Scrolls are Risen 1+2 (I played Risen 2, more pirate-like), The Witcher 1+2 (played Witcher 2), STALKER (played the original, very good game), Arcania (aka Gothic 4), Kingdoms of Amalur, Two Worlds 1+2 (played the first, it was cheesy but fun), Dark Messiah, Dragon's Dogma (might not be like FO/ES but I feel it's close ), Far Cry 1-3 (played FC3, some people claim it's like 'Skyrim with guns'), Fallen Earth (Free to play Steam game, I couldn't really get into it though), Dead Island (It's like Fallout/TES had a three/foursome with Left 4 Dead and Borderlands), and Mass Effect 1-3 (played ME1 and 2)

Games I haven't played yet that seem like Fallout/TES are the Gothic series, Rage (also published by Bethesda), Metro 2033 and Metro Last Light, the Deus Ex series and the Dragon Age series.

MMOs are massive time sinks. I'm currently playing GWs 2, the game is beautiful and only £20.

Call of Duty Modern Warfare 2 , where the dog dies =(

Mount and Blade series if it hasn't already been suggested, though there's not much story.

And if you want something different, but still total open world freedom, maybe Try X3.

Why not give a try to far cry 3 I think i's a nice open world too :P

In terms of rpg I'd have to recommend Titan Quest and TQ Immortal Throne.. Maybe not 'exactly' what you're looking for, but still a great game.. and maybe E.Y.E. Divine Cybermancy for rpg/fps, also a good game.

I've heard some good things about Dragons Dogma and Kingdoms of Amalur

Risen is similar to Gothic since it's made by the same guys.

RAGE is an interesting post-apocalyptic game too.

Space Rangers - Dont know if you can count a lot of solar system as Open World.combat is turn based/arcade(if you play 2nd game you also get strategy with third person shooter) . The whole goal of the game is to destroy the invaders before they destroy you but during the game you can do w/e you want until they destroy you or you destroy them .

Freelancer

Mass Effect.

Fable series, I think You will like it :)
Let me know what do You think about it.

I suppose it might depend on what you end up doing in those games. Personally, I love games where I can just wander and explore and no one really does it like Bethesda. A lot of RPGs have some of that, but you can't usually get sidetracked like you can in a Bethesda game.

Its only 360/PS3, but I've had a ton of fun with Dragon's Dogma: Dark Arisen lately. It has a lot of interesting combat mechanics.

If you do Might and Magic, the first 5 might be odd to play, to me I had trouble getting into the DOS games, but 6-8 are definitely worth a play.