I personally love the 2 games equally (No, that doesn´t mean that FO3 is better because FNV didn´t improve things, I´m just saying that they are so good that is pretty hard to be better, so shut up, mindless "Fallout 3 is better in every single way" masses.
Also, I´ll try to give reason to some of the things said here.
FNV: "The Courier has no backgroung or story" argument - good one, but your forgetting something. He/She is who you want him/her to be! The Tag skills determined who he/she was, what has him/her talents. Over the Wasteland, we find out who she/he was by some characters (The funniest of them all is if you have the Lady Killer perk and talk to the Lonesome Drifter, go stahead and try), and people, come the fuck on, he/she was a nobody because he/she didn´t had and objective. He/she was a normal wastelander trying to survive, until Bam!Bam!, shit happends.
What I´m trying to say is, Fallout 3 lovers who are also Fallout New Vegas haters are most likely nostalgia victims. I played first New Vegas and then Fallout 3, so I´m immune to that. They are both great games, both 94-96%, so please come to your senses.
P.S.: If I insulted anyone or my opinions disagreed with your former ways of thinking, please tell me why. If anyone is gonna waste a message telling me that I´m wrong, at least explain me what makes my opinion wrong and your´s right.