A few thoughts on the various people that fall under the broader heading of "gun owner"...
By far the most numerous category of gun owners fall into the category best described as simply “Owners”. They may own only one gun, or they may own a handful. The gun may have been inherited, or bought in response to current events, such as impending legislation, perceived crisis (Y2K, 9/11, Hurricane Katrina), or a local crime wave.
Owners may never go shooting, or may find their way to the range once every couple of months. They may obtain a CCW permit and even carry fairly regularly and attend a training course or two. If asked what their hobbies were, “guns” or “shooting” probably wouldn't be listed among them. They are probably least likely to “vote their gun rights” although a politician that makes overt noises about registration or confiscation is likely to alienate them.
Hunters own guns to hunt. They may have one duck gun, or a battery of firearms for every game animal that walks or flies in North America, plus one or two for that “Someday Safari”. Hunting requires the least ammunition consumption of any of the major categories of gun usage, since a box of 20 rounds is more than enough to get the rifle sighted in before season and still fill the freezer. In addition to the NRA or GOA, a Hunter is very likely to belong to one or more conservation or outdoors organizations.
Shooters are much like owners, in that they rarely have a huge number of firearms. However unlike an Owner, a Shooter would definitely list “guns” or “shooting” as a hobby. They'll get to the range a couple of times a month, or maybe more, and probably spend a lot of time centered around the hobby, be it reading gun magazines, posting to online fora, or hanging around the local gun shop.
Trainers are what happens to Owners, usually CCW holders, who go to a couple of training classes and really get hooked. They look at shooting as their martial art, and try to get to as many classes as possible. A trainer is easy to spot at the range; they're the one repetitively practicing weak-hand clearance of Type I malfunctions. They consume a fairly large amount of ammunition and are quite likely to belong to several gun rights organizations.
Collectors are just that; more concerned with collecting the guns themselves rather than shooting them. An extreme example would be the guy who has two gun safes full of World War II Japanese military rifles, and only half a box of 7.7mm Arisaka ammunition in the house. Probably the least political subgroup, taken as a whole, unless their particular subspecialty of collecting is threatened. For example, a candidate wishing to ban semiautomatic pistols is unlikely to receive the enthusiastic support of someone with tens of thousands of dollars sunk in Colt's Government Models.
Gamers are people who have been bitten by the competitive shooting bug. Be it NRA High Power, action pistol, sporting clays, or cowboy action shooting, their weekends are likely to be planned around shooting. They tend to have the highest ammunition consumption of any of the types, and as a result are the most likely to be reloaders. In addition to usually belonging to national gun rights organizations, they are also dues-paying members of one or more sports sanctioning bodies.
There is, of course, considerable overlap between many of these categories, especially with Gamers. An active shotgun Gamer is likely to be an avid bird Hunter, a serious CCW-oriented Trainer is often an IDPA or USPSA Gamer, and a Collector of old military rifles may also be a Gamer that competes in vintage service rifle matches. I don't think I've met a gamer, at least outside of some clay bird games, that didn't fall into one or more other categories as well.
Myself? I'd say I was a Shooter and Collector who is in constant danger of becoming a Trainer and Gamer...