I would definitely recommend starting with a 500-600cc bike. Kawasaki has a Ninja 500 that is a great starter bike; however, they also have 2 bikes in the 600 series that are great for beginners. The ZZR600 is the sport and toned down version of the super sport Ninja ZX-636. It still gives you the full fairing style; however, a little more controlled power. Another great starter bike is the new Ninja 650. The 650, also a sport bike, has the style elements of the 636; however, it is also toned down. Although the cc's are greater, it doesn't push as much horsepower or torque. Another neat feature is that, unlike the super sport crouch, the 650 offers a SLIGHTLY raised bar position that allows the rider to gain a little more control and a more comfortable seat position for beginners.

I hope I was able to help a little... let me know if you have any questions. I work for Kawasaki, so I know their product lines pretty well.