[adouglas]

Standard spiel: On the 250, the party starts at 10,000 rpm. Keep the bike wound up and it's more fun than you might think. Many new riders who want to jump up to a supersport right away just aren't riding the bike hard enough for it to come alive. This is also true of those who believe they need to move from a 600 up to a literbike to have fun. You can have tons of fun on the smallest machines.

I mean, with the 250 you've got a vehicle capable of going 100 mph bone stock. In the 60s, you pretty much had to have the biggest, scariest machine you could find to do that, and only those with attachments the size of cantaloupes dared to try. That's what doing "the ton" meant: going 100 mph. On awful tires. With lousy brakes. And crappy suspension fitted to a poorly sorted chassis.

So let's set the whole performance thing aside for the moment. Whether the 250 has "enough" performance is moot. The real question is, does it have enough for YOU to have fun?

So that's the standard bit. Your money, go buy what floats your boat, but you don't "need" anything bigger, yada yada. However... you're a big guy. A really big guy. The Ninjette is a small bike that fits small people well. So is a bigger bike better suited to you? Probably.

When moving up, most focus on the size of the engine. 600... 1000... your original post suggests you're doing exactly that. IMHO that's misguided. On the street, it's not about power alone. It's how that power gets delivered that counts.

What you FEEL is torque, not horsepower.

Go find dyno charts for a typical 600 supersport and a Suzuki SV650. You'll find that the SV makes MORE torque and MORE power than the 600 at real-world RPM, say below 7000. The supersport keeps climbing at higher revs, however, while the SV runs out of steam.

So what does this mean? The "gentleman's bike" SV will be more entertaining in the real world, on the street, where you're not riding around with the throttle pinned all the time. It's often said that supersports are better suited to the track, and one reason why is because they deliver all their performance up high in the rev range. The 600 will walk away from the SV on the track.

I second Ben's suggestion of the SV. The newer version of that bike (the Gladius) has the same V-twin engine but lost all its soul. The SV650S is half-faired; the SV650SF has full bodywork.

Depending on your budget, some other bikes to consider:

Either of the Triumph triples, Speed or Street (triples sound like sex IMHO). Naked bikes, very upright, fairly tall (which would be good for you).
Ninja 650 (to me it doesn't have that much character, but it's a perfectly good everyday bike).
The new Yamaha FZ-09 or FZ-07, which are fantastic bargains. Similar to the Triumphs in ergonomics. These bikes are winners... expect good aftermarket support.
The new midsized Hondas (the 500 and 650). Similar in spirit to the Ninjette... fully faired "sporty" bikes that aren't real sportbikes.

If you really do want a supersport, be aware that they are designed around a very aggressive riding position... leaned way forward, laying on the tank, legs folded up. Basically you ride a supersport like a jockey rides a race horse. Watch people riding these... noobs and squids ride around with elbows locked, trying to sit up. Lots of weight on their hands. It's painful. I happen to like supersport ergos a lot and have no trouble with comfort on my GSXR, but many prefer something a bit more civilized. This is a concern for you because of your size.

Last note: Check the cost of insurance. The Ninjette is stupid-cheap to insure. My GSXR has three times the displacement, five times the performance and costs seven times as much to insure.

Welcome to the sport... be smart, ride safe!