A few years back I realized that I had trouble diferentiating between the movies I liked and the movies I loved from the early part of the year. Roger Ebert has always suggested that this was true of the Academy and why the Oscars have such "short attention span." He recommended a midyear ballot to go along with the end-of-the-year ballot combining both to create the nominations list.
For me, I decided a top 5 usually works. I wait until July 15, since the first few weeks of January are generally a wash for new releases, and so 7/15 is a little closer to the mid-point. This year has been slim pickings for personal favorites. I acknowledge that WALL-E is, easily, the best reviewed film of the year and has already won that Animated Film Oscar— and it deserves it, based on critical consensus. However, it's a No Country For Old Men situation for me, because I liked WALL-E but I can't be dishonest and say I loved it.
I have just seven "nominees" for my top 5 this year— Cloverfield, In Bruges, Forgetting Sarah Marshall, Hellboy II, Iron Man, The Mother of Tears, and Shine a Light.
My top 5 2008 so far (listed alphabetically):
Hellboy II: The Golden Army
Shine a Light