I ride sportbikes but that's about all I've had the opportunity to ride. Four-wheelers a few times but I don't know much about them.
I own a Kawasaki Ninja 250 (starter bike) w/powercommander, shock upgrades, and I run it on 93oct; a very good bike in my opinion, highest power and torque in the 250 class, and great to **** up considering how many [extremely painful] lessons I've learned on it.
I've ridden an R1, and a Hayabusa 1300GSXR - I suggest never straddling either unless you want to kill yourself; because that's how I felt, and I've driven 700+HP vehicles. Way too big and way too much power for my needs (and anyone else's needs unless you're doing track [R1] or drag ['Busa, since they turn about as well as a Volvo asfault layer]).
Such great times, and a great character builder. Whenever I need to do some thinking, I hop on the bike and go for a ride. Who needs tobacco or drugs when you have that adrenaline rush?
Be safe and wear your leathers (gear for non-bike enthusiasts), guys. I've hurt myself too many times and seen others hurt, so be smart and safe!
Edit -- Noticed this was started in April...oh well, won't delete what I spent time typing...what a fantastic bump!