Fallout 3 was a good game. It had good art design, good graphics, good plot...what could be wrong with it?
The graphics are ok. People have gone on for months about how breathtaking the graphics are. To me, the graphics seemed bland and washed out. The water looked good, even from a distance, and that's about where the glory ended. The textures look reasonable, and the view distance is rather impressive for an Xbox 360 game, but otherwise, meh. There are ways to make a game not look all shiny and hyper realistic like Halo 3 without making it boring to look at. The lip syncing is bad, but aside from Half Life 2, there really hasn't been a game that's had truly great lip syncing. It has the same hiccups as Oblivion, particularly with the laughs. Sigh...
Sound is good. Things sound good over all. The voices are good, but for some reason they sound fast. Like the actors were speed-talking through the recording sessions.
Combat-wise, the game feels odd. The VATS system is awesome, but it has no real strategic value. Additionally, the guns feel weak. It's hard to describe, but the gun sounds, models, everything just doesn't feel right. If you play Call of Duty 4 or Left 4 Dead, and compare it to Fallout 3, you'll understand what I mean. They just don't have that kick to them, which overall detracts from the immersion.
But wait, there's more. Despite all these flaws, Fallout 3 does manage to keep you going for as long as it goes. The personalities of the people you encounter are genuine and believable. Characters can actually win you over and make you WANT to help them. The main story is simply very well done. It gives you many options to go through it, while generally ending the same way. However, at the end there is a custom ending montage and speech about your life, depending on what you did in the game. It's pretty cut-and-paste, nothing like "whoa, they made it just for me!", but it still pleasant. The art design in the game is top notch, as Bethesda is known for. Boy, when they need to make an epic world, they do it. While the game does look overly bleak, certain moments will catch you off guard. Just staring up at the fragmented Washington Monument with the sun shining behind it sends shivers down your spine.
In the end, Fallout 3 was a good game, and certainly worth playing. The biggest irk would just be that it doesn't have the kind of side-motivation to keep playing once the main quest is over.