Several 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 mid-year ballot to go along with the end-of-the-year ballot combining both to create the nominations list.
For me, I decided a mid-year 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 (sorry, although it would have been "eligible" I haven't yet seen Spider-Man-- I just can't get excited for a reboot that's premature!).
I have just eight "nominees" for my top 5 this year (the least since 2008)— but three at the top, i.e. "must see" (Moonrise Kingdom, Prometheus, and Seeking a Friend for the End of the World). This year's nominees (films I'd seen by 7/15 that made my "must see" and "recommended" categories) include: The Avengers, The Grey, Haywire, Snow White and the Huntsman, The Hunger Games, Moonrise Kingdom, Prometheus, and Seeking a Friend for the End of the World.
My top 5 2012 so far (listed alphabetically)
Seeking a Friend for the End of the World