This is my favorite sudoku to work, it's called Gatti 5 and you can get it online and print out. They put 5 sudoku puzzles together, I know what you are thinking but it actually gives you more clues. Sudoku is about logic not math, the same puzzle could be worked with color, symbols or letters. Anyway... I like working them!
My website: http://claudiahammer.com
My email: firstname.lastname@example.org
My DPW gallery: http://www.dailypaintworks.com/Artists/chammer-209