Dragon Age Origins (fantasy RPG)
Dragon Age excels at customization of characters, and inter-party relations (i.e. night time sexual encounters, group mechanic)
If you're looking for a fantasy RPG but have already played oblivion, you'll find yourself unsatisfied.
If you're looking for another RPG, go for Fallout 3. I know you're thinking Dragon Age has better replay value since you can play it as the many different races, but the only story-line differences involve the first 30 mins - 1 hour of gameplay.
If you're really looking for replay value, play a Mass Effect game (not a personal favorite). I hear there are a ton of ending and a ton of equally awesome customized characters equipped with unique weapons (you won't be disappointed if you specialize in light sabers or rifles)
I am a fallout 3 fan boy though, because you can go through 2 extreme story paths (savior or enslaver), it's immersive rpg gameplay that's easily accesible.
As with most rpgs, the introduction is SLOW so you can learn the game mechanics. Dragon Age does a great job getting you immersed in their world. It did little, however, to keep me there. Also, I wanted to tell Wynne to STFU and leave my party since the moment she joined in, but she was too good to drop, so maintaining your optimal party can get really annoying... some party commentaries are hilarious, especially if you get the add-on download.
I wouldn't say this game is worth the 40-60 hours it would take to complete ALL of it. But to some who appreciate this genre, it may be due to customization, and immersion.