all games are not created equal

Both games share the same engine (though Fallout's is a little more improved), but Fallout 3 does a lot better. Better 'dungeons', a more diverse overworld, a better levelling system, and more interesting characters make the game a lot more fun to play, and a whole lot less repetitive.

Fable 2 was promised as an open world game full of world changing choices. Instead, what I got was a couple of closed off, linear levels with a Sims like slider configuration for every choice I ,ade. The quest almost always boiled down to "hunt all the bad guys down." However, the combat and spell casting are smooth and intuitive and work very well. And the quest that didn't fall under the hunt configuration were fun and interesting (I especially enjoyed the Captain Dread quest, and the Tomb of Twinblade in the Love Hurts string).
Oblivion is an open world game, were I am free to explore anything and every thing in my own time. The amount of countryside to explore was amazing, though rather bland. The combat was plain; by end game I was doing the exact same combat moves since level 1. Also, the scaling up of enemies made it feel like I never got any pay-off for leveling. However, the quest were fun and varied.
Now, the only reason I say Oblivion is greater than Fable 2 is because of the difference in content. Fable 2 has a far more superior combat system, but the entire game is linear. Also, I only clocked about 20 hours before I finished the game. It took me 10 hours of game play to remember that there was a main story line in Oblivion that I was supposed to be working on. I have played over 150 hours of Oblivion, and I still love the game. I continue to play Fable 2 (I'm really trying to buy the Castle Fairfax) but I feel that the lasting appeal will quickly wear off.

Not that this comparison has been done to death, but now that I've actually spent time with Oblivion, I wish to give my two cents.

We all pretty much get the idea between Fallout and Oblivion.  Oblivion is a quest-oriented medieval fantasy FPS/RPG with axes and swords and spells, and Fallout is the same in a post-nuclear apocalyptic wasteland with guns and bazookas and lasers.

Oblivion offers plenty of customization options for your character, and you level up your abilities by doing, as opposed to the classic experience-earning system of Fallout 3.  In Oblivion, if you run around alot, you level up your athletic skill.  Hop like a maniac to level up acrobatics.  Hell, even if you get wailed on, you'll still level up your armor skill.  With Fallout 3, you complete quests and kill things, you earn experience and you level up whatever you want to.

After the initial dungeon in Oblivion, you're given a huge beautiful world to explore, with fields and forests and lakes and clear blue skies.  You have a map that lists all the major settlements that you can instantly fast-travel to, and even a main quest to point you in the correct starting location.  After that, you take and complete quests as you see fit.

After you escape your initial Vault in Fallout 3, the door opens to a to a huge, horrific and disgusting apocalyptic wasteland, filled with waste barrels, rocks, dead fields, and tin-cans that used to be called homes.  Your initial quest is simply "Find Dad", with absolutely no sense of direction on where to start first.  You can still take random quests as you see fit, and there are plenty of settlements to explore.  However, no settlement has been discovered by you initially, and therefore it is up to you to run the entire way to get to where you need to go the first time.

My issue with Oblivion is it tries to do too much.  There's an overwhelming array of spells and weapons and armors.  There's different guilds to join, random quests to do, and quite frankly I don't exactly understand the leveling system.  I picked my class as a spellsword (or something), completed probably around 6 or 8 quests, and I'm still a level 1 character.  Huh?  Then suddenly I take a quests that involves me killing orcs, and I can't do crap-worth of damage to them. 

Oblivion is certainly a good game, I can see that.  It'll probably get even better as I continue to play.  But simple things like bartering and talking to people is even overly complicated.  Picking locks is insanely ackward and it's best just to use the auto-picking option until it works. 

Bethesda certainly learned from Oblivion when they were making Fallout 3.

The reason I chose Oblivion over Far Cry 2 is for Oblivion's ability to better submerse you in the world it presents.  Although Far Cry is also extremely fun, it was more repetative than Oblivion, and its conclusion was somewhat lacking.  Both games are unique and have interesting attributes but Oblivion offers far more than Far Cry 2. 

This was a tough one... And i know a lot of people will disagree with me here!

'Oblivion' is a vast open world fantasy RPG that gives the player plenty of places to explore, items to pick up, as well as a vast array of weapons to hack the enemy to pieces with. Fallout offers the same, albeit in a post-nuclear world that is more realistic and sci-fi than fantasy.

'Fallout 3' is a great game. A really great game. Bethesda have expanded the game engine to bring greater details to the environment, the tunnels, forts, vaults, etc etc all vary in atmosphere and detail. The scope of the game itself is also incredible. However, the main issue is that the main quest is pretty short. Additionally, the main quest is possibly one of only a few quests that are interestingly put together - many of the other quests i found myself embarking on were, although not unimaginative, a little bland.

Quests such as Oasis were bold and striking in comparison to the Fallout environment, and were a pleasure to play, but these quests were few and far between. In Oblivion, it was the same, there were a few quests here and there that really opened up the environment and highlighted the imaginative ability of some members of the Bethesda team. Garridans Tears was eye opening, and The Dark Brotherhood plot line was eye opening and full of twists. Although both games seem to suffer from this, Fallout seems to suffer the worst: There seemed to be more small interesting quests in Oblivion that kept me playing than in Fallout.

Now, i understand that this next arguement is alittle unfair. SHIVERING ISLES! Now Shivering Isles, the expansion to Oblivion is the most honed, imaginative, addictive thing i have played by Bethesda. The added expansions to Oblivion like Shivering Isles opened up the game world; adding to its replayability. Shivering Isles is what i think every Bethesda game should be like. The Bethesda titles are great games, but seemed to get bogged down in the mundane, whereas some of the expansions they release would almost be great enough as stand alone products.

Nevertheless, Fallout 3 lacked enough uests to keep me interested, in Oblivion, a good amount of NPC's had some small quest to do, or something to tell you, whereas, in Fallout alot of the people seem vacant and useless. There is one major quest, and about 8 minor quests, and then a further 30 or so minor minor ones which simply involve you talking to people, finding people, or shooting things. In Oblivion, I felt that the quests were far more extensive..