1996 zx6r ninja, bike was a POS, i got it painted and running decent and sold it for what i bought it for.  as long as you are responsible and not a retard (see alex for example) you should be fine, just remember that any bike can kill you.  Also most of the time its not the bikes fault but a car/truck that doesn't know you are there.  So just be careful and you have to be a very defensive rider.     
edit:  Start out with a shitty bike so if you do accidently drop it, it won't matter.  i know alot of people have been finding mid 80's honda CB's for less than a grand, that would be my starter bike if i had to do it over again.