A site posting GOTY is almost always in for some serious ridicule. It is impossible to pick a single game that will please every single gamer in the world. Hell, it's fairly improbable that 1/4 of them could narrow it down to less than five. Many sites take the easy way out and make the award a popularity contest, but I am quite glad to see that Gamespot has not.
Though I haven't played Demon's Souls yet, I have heard nothing but how revolutionary it is (well, that and the crushing difficulty). Everyone says it is unlike anything you have played before. What other contender for the award could claim this? The next closest competition would probably have been Uncharted 2. This title may have been an absolutely amazing experience, but is it really anything more than an incredibly refined and polished Tomb Raider? The basic gamplay mechanics are relatively unchanged and pretty graphics can only carry the game so far. Eventually, I felt myself saying "I've done this before." I don't mean to imply it doesn't deserve all the praise it's getting. I would rate it around 9.5 or so, but I don't feel it should define the year in gaming.
Calling for Modern Warfare 2 is even worse. Just because a game sells well does not mean it represents the best of the year. The set-pieces may have been bigger, but the plot was far worse and the mulitplayer was basically the same with new maps. As with Uncharted 2, I'm not knocking this game's review scores, as I myself put a few hours into it about every other night. I simply don't feel it represents the best of the best.
The above examples beg the question, "Should a sequel ever be up for GOTY?" Sure, if they do something completely new, but when has that happened? Most sequels are merely tweaked versions of the original, carrying over animations, graphics, weapons, characters, and most other aspects. Rewarding rehashed aspects isn't a good message to be sending to developers. Why would they ever try anything new if the ultimate goal of any game, a GOTY award, will be earned with the same stuff they did last year?
Not having played Demon's Souls, my personal choice for GOTY is Borderlands. It takes two genres never blended so seamlessly before and wraps it around a game that is just plain fun. Not only is it unlike anything I've played before, but it is also the first game that I continued playing after getting every single achievement. Sure, it wasn't perfect. The graphics could have been better, environments more detailed, and a few glitches snuck into the original retail version. However, nothing else this year that I have played has moved the industry in a new direction, which I feel should be the main goal of any game released. It's for this reason that I whole-heartedly support Gamespot's decision to go with a less popular but more unique title.