I've driven both. I own a Yamaha V-Star 1100 "cruiser". My brother has a Kawasaki ZZR600 Ninja. They're both nice bikes, but totally different machines.
Driving style - My bike has tons of low end torque. It's quite comfortable just crusing around without lots of throttle. What the Ninja lacks in low end grunt, it makes up for in high-revving power ... but you have to rev it to get there. Not much fun for cruising around town, but a blast to drive out on some open winding roads.
Passengers - HUGE factor. Yes, you can technically take a passenger on a sport bike. She will most likely hate you for it. My g/f can't stand being on the back of a sport bike. And if you have to make a quick stop, she will slam into you, and your family jewels will slam in to the gas tank.
Comfort - My bike is comfortable up to about 75 mph. Above that, the wind really beats me up. I could put a windshield on my bike, but I don't like the look. The Ninja doesn't get comfortable until about 70. At that point, enough wind is hitting you to relieve the pressure on your arms. At around 90-100 is where you start tucking the tank. At 130, you know if it's comfortable or not because you're concentrating on not turning into a grease spot on the road.
Everything else comes down to style preference - looks, sound, etc.
my $.02 from riding both kinds.