It all really depends on what you want to do with the horse, and who would be riding if someone would even be riding it.
A Quarter Horse is a good werstern competion and pleasure horse with a sweet attitude and williness to learn, sorta like a lab in dogs.
A Shetland Pony is a good first horse for a child for pleasure and competion in hunters, also sweet and loving but sometimes moody.
A Lippizaner is a good choice if you plan to get into dressage, with beauty and grace are simply georgus but sometimes will cost a pretty penny, I don't know to much about thier attidude though.
A Paint is a good coice for pleasure and relaxing on the ranch as well as western compitetion, sweet and kind a good childrens horse.
A Warmblood of any type is usally good for show jumping and is also very pretty, but agian probably cost a little bit of money and agina i'm not to keen on thier personalities.
A Thoroughbred is a good horse for racing, but also good and even tempered but can have alot of energy and want to run.
Last an Arabian is a geourges horse, called the most beatiful, but has a stubborn attitube often though its not true with all of them can be sweet and used in dressage, hunters, and even pleasure.
For age of your horse if its your first i suggest a horse over 16 unless you have alot of riding expierence. And make sure you fins a good farm so you know exactly what kind of horse your getting you don't wanna see a beatiful horse and jump and buy it with only seeing it once, because it might turn out to be a monster, ;), also make sure you know of any health problem or if anythings common to the breed your getting because you don't want to have to pay lots of money for an ill horse all the time, unless you intend to be a shelter of some sort.
Well, I hope this helps you in your horse buying ventures!:)