Wasn't sure what to pick until I noticed a certain game in the other-list. Still, I could mention a few honorable mentions.
The first Uncharted was a good game, but lacking in several areas that made the following titles in the series truly great. The gameplay in particular was still quite unpolished. Bioshock also deserves a mention, but I didn't play the game for the first time until, and a lot of the impact the game initially had was lost since I was very well aware of the big twist. Still a great game, but the solid gameplay and good writing aren't quite enough without the added shock that the big moment had back in 2007. Crisis Core is the best game on the PSP, but not quite on par with the best games of the year in general. The story is very good, and the added background to some of the minor characters of FFVII is great, with a wonderfully emotional final chapter, but the limits of the hardware and the repetitive gameplay holds it back. Finally, Portal was for a very long time my favourite game from 2007. Genuinely one of the very best puzzle games of all time, with a near perfect villain to boot.
Yet, the game I will vote for, is Lost Odyssey. Effectively a Final Fantasy in all but name, at the time of its release it was well-received, but also somewhat maligned for what some people perceived as outdated gameplay. These people are wrong. The gameplay is great, the characters and story are very good, in particular the stories that detail past events in the characters' lives are wonderful, and the music is excellent. The one real drawback the game has is its long load times, and that's a minor grievance at best. I doubt it'll win the vote, but as far as I'm concerned, it's better than any other game released in 2007. Of the ones I've played at least.