YamaPi - who is the most brilliant in Nobuta wo Produce...It's like he's not acting, but improvising all the time in the drama.
Matsumoto Jun - love all his roles, started with Hana Yori Dango
Shun Oguri - One of my first favourite actors, love him since Hana Kimi, the best of all as an actor, I think
Toma Ikuta - Again, love him since Hana Kimi, recently watched Maou, brilliant
Kazuya Kamenashi - here I'm soooo no objecitve :) He;s brilliant for me in everything he does, either singing or acting...:)
Kenishi Matsuyama - fell in love with him after watching Death Note, love his acting since then
Tamaki Hiroshi - though I haven't watched many movies with him, just Taada Kimi wo Aishiteru and Nodame Cantabile, these are enough for me, to like him
Masaki Okada - loved his acting in Boku no Hatsukoi Kimi ni Sasagu and Otomen :)
Though there is more, I'll shut up :P