for what a decent 250 will cost you, I'd buy an F2 or F3. the 250 is a great bike, but its strength is flickability and corner speed. I hold back on both of those aspects of riding on public roads. for street riding, I find the most enjoyment in good acceleration, and more 'planted' handling. A 650 would be great, if you can find one cheap enough, but like I said, old Honda 600's should be pretty cheap and easy to find.