I have finally gotten a chance to play around with Fallout 3 myself, and here are my first impressions and a few tips for beginning players.
First of all, the atmosphere in the game is perfect. The post apocalyptic feeling oozes off the screen, the music (which is heard on the various in game radio channels you encounter) is exactly what you'd expect from a world stuck in the early 50's, the design of the world makes you feel like you are really there. What would America look like after a nuclear war ? i think exactly like this, including mutated cows and humans deformed from radiation sickness. I don't think there's much they could have improved to make it feel more real. The story-line is engaging and I found myself having a hard time pulling myself away from my XBOX to go to bed.

I'll try not to reveal/spoil anything from the actual story-line, but I will give some small tips which should prevent you from having to restart the game (too many times) to do the stuff you missed out on...
First of all, the battle system works in 2 modes, real time and turn based. To enter the turn based mode you have to hit the right shoulder button on the XBOX controller, WHEN YOU HAVE AN ENEMY IN VIEW. You can then select targets and specify body parts to target with your attack. This is like a 3d version of the original battle system in Fallout 1 and 2 as you will be using up AP's (action points) for each move. This is also the mode where you will be experiencing the best gore as heads are being torn off and blood will be flying everywhere in slow motion. Gruesome !

Then there is the equipment repair system, which wasn't entirely clear to me form the start. Not only does it require a certain repair skill level to repair certain items, you will also need materials to do the repairs. So what materials do you need ? The scrap metals you find throughout the game would seem like a logical option, but in fact all you need to have to repair items, is another item of the same (or similar kind). So find a few of the same armors and you can repair one of them, using up the other ones in the process. The same goes for weapons, and as I said, similar items are often good enough. I was able to repair a 10mm pistol, using a 10mm silenced pistol for instance and the same goes for armors that are similar enough. I personally think this repair system is a huge improvement over the system used in Oblivion (where you used 'magic' repair hammers that could repair anything in the game).

Trading with merchants in the game works a little different than in Oblivion too. The merchants do not refill their cash (bottle caps) so quickly, or as far as I could tell, not at all, so it's not so easy to gather huge amounts of cash in the beginning of the game. But if you spend money at a merchant by buying items, or repairing items, this money will be available again ... remember that when you are selling them items. Another important note regarding trading is that if you are selling stuff to a merchant, but it's worth more then they can afford, there is no warning whatsoever. So keep an eye on how much you are trying to get rid off and don't give away additional items when the merchant is out of money !

Traveling around the game world seems like an effort at first, but this is merely because you have to have 'found' several locations on the map before you can fast travel between them. If you are over encumbered, you will not be able to run, jump or fast travel .. You WILL be able to walk around though which is a huge relief to what we are used to from Oblivion. I'm sorry to keep mentioning Oblivion in this quick review, but it's hard not to use it as comparison when it's based on the same engine and so many things are similar.