i would suggest a 500cc, perfect for commuting. as far as a first bike, mine was a cbr 600 f2. then up to a 1000cc gixxer- which was a bit strong- although it was stolen. now i have a cbr 600 f4i-- perfect bike. strong motor, nice chassis, sweet lines.
its all what your want from your bike, commuting, sport riding, stunting?? get a bike accordingly. good luck!