Whatever improvement in looks you think you will get with the wider tires you will give back in actual handling. Don't go wider than 110 up front. Personally I went with stock inch sizes on my 750F, which is 19 front/18 rear with Metzlers.
My 550F, which had Lester alloys on it (I switched to wires recently because I am selling it) has 100/90-10 front and 110/90-18 rear Shinko 712's. Both the front and rear Lesters are 2.15" wide. The wires are both 1.85.