I learned on a Katana... Huge mistake! They are too heavy!

I would suggest a GSR500F if you are a lightweight person or a Gixxer600 if you are a little heavier... The only thing about the R6 - It's a VERY lightweight bike with a lot of getti-up... I'm not a big fan (they look great, but I don't like the way they "drive" or ride, and the back seat is very uncomfortable if you are planning on ever taking on passengers.) The Gixxer 600 is a great bike, solid, smooth, just great all around!