I started out with the Ninja 250 and progress up from there. Right now, I am riding a CBR600RR. I agree with everyone - start off small, don't jump into a large liter bike. There is a new Ninja 250 just came out...it has a nice body and all-around starter bike.
http://www.kawasaki.com/Products/SubCategory.aspx?id=6
edit: Forgot to post - this is the vendor that I got my helmet from...they are internet apparel/parts sales peeps. The "small" store is located in DE
http://www.kneedraggers.com/