There's a few for me: Yuuko Ichihara from xxxHOLiC [pictured] Mion Sonozaki from Higurashi: When They Cry Ryner リュート from The Legend of Legendary Heroes Rui Ninomiya from Gatchaman Crowds, to some extent (*cough*I wish I was that smart *cough*) Light Yagami from Death Note, to some extent (*cough* God-complex *cough*) Milly Ashford from Code Geass
Honestly, I dont have a single character that reminds me of me as a whole, but I have a long 一覧 of characters that remind me of certain aspects that make up are/were large factors of me.
There are A LOT of characters each with their own traits and Mashiro Shiina is one of the most similar to me, not just because of her personality, but also we both 愛 art :3