My first book of 2012! I've finally read The Hobbit, and it was a good read - it had a similar writing style to The Lord of the Rings. I really enjoyed getting back into the Middle-earth world again, although I have to say I missed the elves and the men.
The ring isn't the central interest of the story - that lies with the dragon Smaug - and yet it plays a crucial role. Bilbo Baggins discovers the ring early on in his quest with the dwarves, and all his future adventures are tied to it. It helps him escape the goblins, because of it he manages to save his friends from the spiders, from the elves, and from the dragon. The hobbit seems to have a lot of luck, which is why Gandalf had such implicit faith in him as a companion for the dwarves.
As for the "central interest", I didn't find it too interesting. That's because, although the dragon (and the gold) was the destination, it wasn't the high point of the adventure. When the dwarves and the hobbit finally reach the dragon, the novel isn't as intense as I expected. All the adventure had been played out before hand with the band's confrontation with other enemies. The novel lacked the depth that Tolkien was to give the more popular sequel. The history of the characters wasn't given in such detail and over all the novel was more light-hearted - the doom of middle-earth wasn't in everyone's mind. But all in all, it is a good prequel to The Lord of the Rings.