Whats a good bike for starting out?

Ok some im 22 and am about 6.1.. Im looking to buy a bike within the next few years maybe even this year. Now as of this second i have zero experience on a bike but before i ever buy one im going to take all the saftey courses that they offer. Now iv heard things like 250cc are great bikes and even to the point that its absolutly not advisable to buy anything over a 250cc. Here is the problem whatever i get im gonna have for a few years and iv heard that 250cc gets bored really fast. The most driving im going to do is in town 30 mph driving to class especially at the begining and i will never do any driving that is stupid such as 100 mph. And im not looking for a cruiser just a sports bike. what cc should i look for that i will be able to enjoy for years and not get bored but still be able to handle. Also eventually im going to buy a Duc 848 how much experience should one have before buying that bike (yes i know the repair and everything is expensive if dropped, money is no issue here) Thanks for the help