I'm going to have to side with Jeff on the Angry Birds argument. Look, no matter where you stand, Angry Birds is just plain fun (to a lot of people anyway) and most importantly, it's a game that appealed to both the casual and "hardcore" audience.
To discredit it just because it doesn't stand at a technical level is shallow and subconsciously puts us in that mindset of "Games must look great to pass the GOTY test" and sure it's a huge technical difference to lets say, Mass Effect 2 and you can liken the situation in movies where a short indie film winning the Oscars, but that shouldn't even matter in the first place.
It's still a game and If it brings in the fun and gave an awarding experience to various groups of people, then it's proven itself already. Hell in an extreme case, if Zyanga somehow managed to make a great game on Facebook game that applied the same concepts and roped in the casual and "hardcore" alike then I wouldn't discredit that getting a GOTY either.

Now my only problem is that if Angry Bird's had won, I would be confused. Because although fun, it was up against some really stiff competition. However keep in mind we were discussing whether or not Angry Birds deserved to be a GOTY nominee in the first place, not winning so pardon me if I sound a tad hypocritical.

Now I have to bring up a question. That is, would anyone personally give a video game GOTY nomination to lets say, a technical, unique and original experience which wasn't really fun, but something in which no one has ever seen/played before? Or give it to something that was highly unoriginal, but truly fun and polished?