have a friend that routinely rides his 2004 gsxr 600 from richmond to NY and is about to ride to california and back... i've done a few 500-600 mile days on my gsxr's and felt like i could keep going

on my 1000 with some aggressive riding and speeding i get about 40 mpg, if you take it easy and do the speed limit you might be able to get 45+ mpg, i'd guess a 600 would do even better, also another advantage is my ride home from work is usually pretty heavy traffic and its alot easier to get in and out of cars on a bike

so monthly cost to own and ride my bike during the season i'd say...

payment(financed full amount plus extended warranty)- $220
insurance- $100
maintance(average of tires and oil changes since they are less than montly)- $100
gas- $50

so for me, $400-500 a month for a brand new 1000 while i'm financing it with really high insurance, if i keep it for 4 years after i've paid it off then that average cost would drop since i'd be making no payment... if your older and have reasonable insurance, and get a used bike for a less i'd say you could own and ride one regularly for less than $200 a month