Thanks to mabo for the picture

and to everyone who has voted
Well, I've put over 90 hours into this game over the course of three characters (my first playthrough completed after 52 hours, missed most of the side quests), my second, interupted by the arrival of trophies and my third, started for that reason.
I think you won't be surprised if I say I like this game!

Ok, so I suppose I had better answer the question as to why I like it.
From the moment the intro started with the pan out scene from the bombed out bus with "I don't want to set the world on fire" playing in the background, I couldn't take my eyes off the TV. Then came the intro proper, a haunting narration about war, how the world came to be as it is now along with images of a post-apocolyptic world of tomorrow and an introduction to your home-to-be, Vault 101.
That's when the game starts, with your birth, the creation of your character's appearence and name. You're talked through the process by your father, the central protagonist of the main quest and delightfully voiced by Liam Neeson.
The tutorial consists of playing through segments of the first 19 years of your life (something that only takes about as long as Oblivion's tutorial for those of you who have played that game) and ends when your dad decides, for an as yet unknown reason, to leave the vault. You are then forced to follow in his footsteps and leave the safety of the vault yourself. During the tutorial segment, you are introduced to the various gameplay features such as V.A.T.S, a sort of pause/bullet time combat and the concept of Karma. So depending on your moral choices, you leave the vault as either a villain or an outcast hero.
The moment the vault is left behind and the blasted wasteland that was once Washington DC opens up before you, the name of the game is freedom. Go anywhere, do anything and play the game in any way you like. This was a great thing in Oblivion and is implemented even better in Fallout 3 thanks to the hopeless struggle for survival that pervades the early hours of gameplay. The quests are interesting, the characters seem much more real than those found in Oblivion and the karma aspect of play can really make you feel involved with the world in a way you never could in Oblivion.
The graphics for PS3 are good, no where near as bad as you may have been led to believe by the reviews. The only bug is the lack of DLC as it's a Xbox exclusive. However, I remain optimistic that us PS3 players will see DLC at some point (may not happen but I hope).
To conclude, I think you should give this game a try. If you had an interest in Oblivion but was put off by it's magic and goblins theme, Fallout 3 may well be the game you're looking for!