Absolutely buy used! Having owned more than 25 motorcycles in my life, but having only bought 1 of them new, I have some great guidelines for your purchase:
1) Avoid buying a used motorcycle from a dealer (the dealer either had to purchase the bike outright from an auction, insurance company, finance company, or the owner himself/herself), that means that in order to survive, the dealer MUST mark it up. So, buy a used bike from the owner.
2) Make sure that the owner has kept ALL of the service/maintenance records, and make sure they have the title "in-hand". If they have not, then pay them substantially less than they are asking for the bike. It is always helpful to try to judge the previous owner's attitude toward the bike & condition of it. Never buy a bike from someone who does not care for it. Peoples' attitudes toward their possesions reflect greatly on their "care & feeding" of them.
3) Spend at least 10 minutes carefully looking over the bike; bring a flashlight & expect to crawl around on the ground. Look in every dark nook & cranny. Look at the frame, exhaust headers, underside of engine, sidecases, forks, brakes, rear shock, grips, under the seat, tire wear,etc. Actually, I try to look at so much stuff that the owner begins to feel nervous. Here's a tip: the longer that it takes the owner to feel nervous, the higher likelihood that the bike is in top shape.
4) Test ride the motorcycle where you can get up to at least 40mph in a straight line & let go of the handlebar to see if the bike pulls to one side strangely; if it does, WALK AWAY Test condition of brakes, shocks, steering bearings, etc while riding.
5) Show up with cash & make them a cash offer for 10%-15% less than what you are willing to actually pay for the bike, but please remember that your cash offer should be reasonable & respectful (but, who knows, you just might get it for that). There is something very difficult about refusing a cash-in-hand offer. Please, please, please do not insult the seller with an offer that it substantially less than fair-market-value.
If you have done these things, you are very likely to get a fantastic deal on a great used bike.
As for me, I just picked up an 08 FZ6 with 5,600 miles on it that was immaculate for $3,700!! (It was sooo clean that I was willing to pay $4,000, but they accepted $3,700 which allowed me to purchase & mount a set of new Michelin Pilot Powers) AND I LOVE IT!