The 250 and 650 are both good starter bikes. Why are you looking new though? You should be looking at used bikes. No matter how careful you are you will eventually drop it and then you'll be sick. Buy a used bike for a lot less money then when you have ridden for a year or more, step up to a new bike if that's still your desire. Stay away from the 600 supersports for your first bike - CBR600RR, R6, GSX-R, ZX6-R. Lots of people are going to tell you that "you'll be fine if you take it easy," but read the other new rider information on here for more reasons why. You're already on the right track though.
"We didn't trade shoves; I did all the shoving." -Bobby Knight, 1981