If this is your first motorcycle, I would suggest a 600-800 cc (Yamaha or Kawasaki). If you have rode bikes for awhile, go for a Harley Davidson Fat Boy. Both of these motorcycles are stable and easy to ride. They hold the road well and are easy to maintain. Shop around and deal with reputable dealerships.

There are many things to consider when looking for a motorcycle.

1: Will this be your first bike or are you an experienced rider?
2: What is your primary use for a motorcycle (commuting, cruising, long distance touring, sport, adventure, off-road)?
3: What are you willing and/or able to pay?

If you are a new rider the first thing I would consider is taking a Motorcycle Safety Foundation course. It is invaluable for getting you up to speed on street riding. http://www.msf-usa.org/

For a beginner, never buy something too small (engine and bike size) as you will out grow it very quickly. For the petite or shorter in stature I would recommend a bike with a lower seat height that allows you to comfortably place your feet on the ground at a stop.

The following are good bikes to consider that you will not outgrow too quickly:
Suzuki SV650 - unbelievable all around bike

Harley-Davidson Sportster 883 XL - All the style for a lot less money. They have a neat trade in program where you will get full value toward a larger bike.

Triumph Bonneville - Classic styling, great engine, low maintenance.

Suzuki GSX650F - Sporty, but comfortable.

Honda Shadow - Great line of cruisers, typical Honda reliability. Comfortable.

You can also consider a used motorcycle which will open up options as pricing goes. A Ducati Monster is far more appealing when found on the used marketplace.

The list can really go on and on, but in the end it will come down to price, personality, use and stature (body). Feel free to contact me directly to talk more!