First: Take a class, most are through MSF (motorcycle safety foundation)
Second: Don't buy a Duc to learn on, they are super expensive to maintain ($1000 service every 5000 miles or so, oil change, valve adjust, all that stuff) Buy a unintimidating used motorcycle, learn and ride it for awhile then define your criteria for a bike and buy what you want.
Third: Be careful! Some people have the mindset to ride and some just never will. I know a guy who took the class, got a MotoGuzzi 750, then went for a ride with me and crashed in the first corner, not going very fast.
And no, it is not a given that you will go down learing to ride. I have ridden dirtbikes for many years, then switched to the street this spring. I have ridden about 3500 miles on the rode now and have had no issues. But my dad with about 100,000 in the saddle has been teaching me how to ride correctly and defensivly and that helps.
BTW: the people doing wheelstands down the interstate at triple digits just piss me off, cause they give motorcycling a bad rep and raise my insurrance rates. Loud pipes DONT save lives, there just annoying.
'Tricks are for kids.'-Stephen Koch, snowboard mountaineerer (six of seven summits), in response to the question 'What kind of tricks can you do?'