While not my cup of tea, Fallout 3 is a great game that is a worthy investment.
Fallout 3 opens with your character being born and his/her life developing in vault 101, a claustrophobic fallout shelter built to withstand nuclear war (something it accomplished quite well). At the innocent age of 19 your dad does what is thought to be impossible, he leaves the vault. In order to save your life from the furious overseer and find out what happened to him, you set out on a journey through the capital wastes in hopes of uncovering more.
The gameplay takes you over what little is left of D.C.; shooting, smooth talking, sneaking and making tough decisions all come into play as you explore the godforsaken nuclear desert and survive it's inhabitants. More interesting than the shooting is the moral choices you must make, which will either make you feel like a hero or an abomination by the end of the game. the game if fun in that it is creative and gives you a wide number of options to tackle any solution, from picking locks to reasoning with enemies, or simply ashing their faces in with clubs. The weakest aspect in the equation is the shooting, which is necessary at times but ultimately is underpowered if you don't use vats. Get used to missing if you don't focus.
The world is as it should be, bleak and desolate. This game is immersive, but by no means beautiful. It's difficult to enjoy watching endless desert broken by collapsing buildings in said desert, but the fact is this world looks as a post nuclear blasted world should. What new buildings are around are made from scraps, while old buildings crumble without maintenance and years of radiation and lack of clean water has prevented much of anything from surviving long save for mutants. More enjoyable that the wastes are the brief glimpses of what life used to be like in this world through clever foreshadowing and detailed artistry.
The sound is varied on scale. While voice acting and general sound effects are good, gunshots and tension are as underwhelming as can be. It makes you feel like your having a paintball fight, not an intense battle for your life. This detracts greatly from the world and makes weak weapons feel weaker, while making the points in between battles feel like a saving grace. The music is subtle, and ominous.
Playing through to the end, minus the side quests, will take a large chunk of time and give you plenty to do. The game has multiple endings, but none are so different that you will feel like you're missing out. The replay value is in the ability to tackle the same scenarios in different ways, which is a good source of enjoyment. If you can tolerate some weak gunplay and enjoy a good rpg, then you owe it to yourself to give Fallout 3 a chance.