Fable has its flaws, but the overall rpg is highly enjoyable
For starters, Fable is a relatively pretty game. Although it doesn't push the massive polygon counts of more recent PC games, Fable's art style really presents the world of Albion well, and gives a real endearing quality. The world of Albion is quite restrictive, though, as you pass from area to area a la Metal Gear Solid. I would have liked to see the world more open-ended.
The sound of Fable has its qualities and shortfalls. Sometimes the background music is well-composed and fitting, while other times it isn't as good, depending on where you are and what situation you're in. The voice acting is well-done, but nothing spectacular. The area needing the most improvement is combat sound, where contact with the enemy just doesn't convey the visceral feeling of battle.
Fable's core gameplay is solid, but the gameplay difficulty is biased in the player's favor. It is simply too easy to defeat enemies later on - you can use a variety of magic attacks to slow down the enemy, then warp behind them, then attack them multiple times before they get a hit on you. Not to mention that you can purchase resurrection phials that will save you from death. While it's a great feeling when you attain these attacks, the gameplay difficulty imbalance makes bosses a breeze. So if you're a gamer who likes to be challenged, just know that Fable doesn't provide much.
The story and characters of Fable are not very interesting, and this is a major impediment to the game. The main unique aspect of Fable is the ability to be good or evil, but this mechanic proves to be more of a gimmick, as you can quickly become evil by killing lots of innocents, or buy your way out of evil at a certain point in the game.
The main flaw of Fable: TLC is that it's too short. Although the original Fable is an even shorter game, the additions to TLC still seem insufficient, and this depreciates its value in comparison with other rpg's.
Fable may be a flawed game, but what makes it worth a play-through is the combination of the world it presents and the enjoyable aspects of the gameplay. The various quests that you can embark on give this game a sense of variety and adventure. You can do everything from rescuing traders to taking on villains, getting married to kicking chickens, flexing your archery skills to boxing fellow townsmen. The sense of freedom to do so many different quests is really what makes Fable: TLC a worthwhile experience.
So if you're looking for an rpg with a good art style, a good sense of humor, and lots of quests to offer, give Fable: The Lost Chapters a shot.