When I had first played Fallout 3, I had not been a really amazing fan of the series to start. I had played, finished, and enjoyed Fallout and struggled with and never finished Fallout 2. Fallout 3 was the chance for a new developer to take the series in a new direction. That direction went from the classic D&D-style turn-based RPG to the Action RPG that we see today. What was lost in complexity of story and sheer dynamic of the world was replaced by a run and gun shooter with RPG elements.
Whether you feel that change is in the best interests of the genre depends on how much you liked the old games. I can sympathize with the old guard fans who feel betrayed at the dumbing down of the series. The original Fallout universe was a multitude of shades of gray rather than the homogenous brown that attempts to feed in black and white choice into the game in the newer entries. The dialogue in Fallout games since 2 has been the thing of memes and one has to wonder how much more simplistic it can get. The lack of strategy needed to play the game has gone away in exchange for an inventory management simulator.
But despite this, Fallout 3 is still incredibly fun. I still find myself tuning in to President Eden's speeches, I want to hear Three Dog's assessment of my story with his swagger attitude that he brings to the repetitious radio station he runs. While the combat is more reminiscent of a shooter than an RPG, it still is fun and no matter how many times you see it, an exploding slaver head is always satisfying. Sure there is little "choice" in the game's endings, but I still look at the story fondly and sometimes find myself wishing that Liam Neeson would be my father.
The graphics are dated, but you can still enjoy an alternate Washington D.C. and still get lost in the world trudging through a post-apocalyptic action role-playing game.