I just finished the book, and I am quite impressed with Mr. Paolini's work. The writing is quite good, as are the characters, the conflict, and the setting. I do not think the trilogy is a rip-off of LotR, and I say that as a writer, a literary expert, and as a lifelong Tolkien scholar. However, it is easy to see the unmistakable influences of and references to Middle Earth. But come on; no one has suggested that the book is ripping of Beowulf. The dwarf king's name is Hrothgar, for Pete's sake. And then there's the ever present wyrd. These are simply reflections on the Anglo-Saxon culture that spawned Old English. Wyrd is the name of the goddess of fate, and wyrd (lowercase) is fate. There are many inventions of language based in Old English (with Latin overtones) in the book. There are also hints of mythology from several cultures. Theoretically, you could say that the Tolkien reflections are mythological, since he did create a mythology for a country that didn't have one.
I'm not touting Paolini as the next Tolkien or the next anybody. What I am saying is that any similarities show that Paolini is a Middle Earth and English language scholar in his own right, and imitation is the sincerest form of flattery. The world he has created and peopled is an immense accomplishment, one he drives home with poignant and precise prose and a knack for narrative. The accomplishment is augmented by his youth, but it is diminished by what we are doing here -- reminding ourselves that it has already been done. Let us give credit to young Paolini for his accomplishment and not begrudge him any similarities to any of the masters he emulates.