First I would like to preface this by saying that, I have owned, raced and worked on several different styles of bikes; everything from Supercross, Sport bikes to small and large cruisers. With that said, most of your Jap cruiser bikes have the same basic frame dimensions, meaning they are designed for someone on the average height of 5'9" to 6'3", and them fit comfortably within the saddle.
To bring up a few points that you may want to consider before buying your first bike, keep in mind that if you buy a smaller cc sized bike and want someone to ride with you on the back, the bike is going to be down on power. Smaller cc bikes such as the 650 v-star and Honda bikes have drum rear brakes. When it comes to maintenance that is the worst design to work with, while the bigger bikes like the 1100 or 1300 will have disc brakes all the way around. A lot of the smaller cc bikes have carburetors while the bigger bikes will have fuel injection, this may not matter if your buying a new bike because almost all new bikes have fuel injection (I believe anyway).
However for myself, one of the largest factors I look for on a bike is, air cooled vs. liquid cooled. There really isn't a big point on bikes that are driven up and down the freeway and don't deal with a lot of stop and go traffic, but for bikes that do, it matters a lot. V-twin bikes that are air cooled and sit in stop and go traffic a lot, tend to get hot on the back cylinder and burn oil in that cylinder. Its not enough to notice on a single oil change but over time you will have problems with that cylinder. The liquid cooled don't have this problem with oil failing and gumming up the oil passages.
Now to throw in my two cents on the manufacture debate. I have worked on all brands of bikes - Kawasaki, Suzuki, Yamaha, Honda, Harley Davidson - they are all good bikes if they are taken care of like they need to be. My only concern is with the Harley Davidson, its hard to find NON Harley Davidson shops that will work on Harley bikes. So if you don't have a local Harley Davidson shop, then you might have to deal with loading the bike up and taking it some where far off to get it worked on. I would drop by my local shops and ask if they work on Harley bikes before buying one.
With all of that said, good luck, and if you have any questions hit me up and maybe I can help you out some.