My LBS sold me a bike far to big for me. I couldn't figure out why I wasn't enjoying the the ride. I didn't read up on "how to buy a bike" and was sold a new bike from the previous year that he had to get rid of. 1"-2" for road or city bike. 2"-3", some say 4"-5" for mountain bike. This is the clearance you should have between your crotch and the top tube when standing flat footed over the top tube. I'm 5'-10" 285 and have been happy with my Marin San Rafael (hybrid/city), this was the second bike I had to buy. This bike fits. Do your homework and you'll make a good choice. Here are some links I wish I'd have read before investing twice.
Bike 1
Bike 2
Bike 3