Optimum defensive range	price	Training time	Tactical use
Pistol Low End: Used Glocks, XDs, revolvers High End: Custom 1911s, HK Sig	0-20 yards	Medium range $300 for some reliable models used to $1k	Very high, developing decent pistol skills takes over 1k rounds of ammunition and good instruction.  Pistol skills are more perishable than long gun skills as well, and require more maintenance practice.	It is the only weapon you can have with you in any situation that requires concealment.  Therefore it is only choice for normal operations outside of your house.  It is a better weapon when threats are within “grabbing” range.
Shotgun Low End: Used Remington, Mossberg pump models High End: semi auto Benellis	4-50 yards	Good used models for $200 or less, high-end models might run $1k but are unnecessary except for competition.	Very low, it is possible to be minimally proficient with a shotgun after one dry practice session and one or two trips to the range with less than 100 rounds of ammo expended.	Shotguns with good defensive loads have devastating damage potential within their optimum range, but lose to rifles at longer ranges. They have severe disadvantages outside of a home/yard defensive situation.
Carbines Low End: Keltec SUB2K, WASR rifles High End: AR15s quality AK clones	4-300 yards 4-100 for pistol caliber carbines	Mostly over $500, maybe under $300 for a used pistol caliber carbine. $2k or more for high end ARs with optics.	Medium to high.  The use of a carbine in short range defense is much easier than with a pistol (past 10 feet or so) but using it to its maximum ranges is more difficult.	The defensive carbine is the most versatile small arm available.  It is able to do everything the pistol and shotgun can do (except be concealed) and is able to reach out past 50 yards.
Battle Rifle: Low End: Saiga 308 CETME, “Franken” FALs High End: DSA FALS HK91 AR10s M1As	4-600 yards	Usually over $1K for average models, higher end models can easily run $2K	High, close in shooting requires more time to master vs a intermediate caliber carbine due to recoil, and shooting them at longer distances is its own art form.  Practice ammo is also much more expensive.	Battle rifles are in their premium when you might need to penetrate cover such as cars and brick walls. They have a disadvantage when operating in any kind of close in environment, such as from a car or in a building.
Curio and Relic rifles	50-300 yards	A lot of variance depending on condition. $100-$500	Training time for minimum competency is quite low as most are fairly ergonomic.  Again, shooting at longer ranges is another story.	Tactically limited compared to most semi auto rifles, most are long, have low magazine capacities and are both slow to reload and fire.  They are hard hitting at a longer range than most intermediate carbines.
Hunting Rifles	50-500 yards	300+ without optics	Training time at maximum range is quite high and probably requires special instruction.	Tactically limited due to magnified optics (poor at close range) and typically bolt action.
22LR	N/A (not defensive weapons)	$100+	N/A as these are for training time	Minimal tactical application except as a last ditch defense.  See notes for uses.

Pistols: Pistols can be concealed, as such they are the only solution when you need a gun on you, outside of your home, that does not start out as a defensive situation.  There is a lot of romanticism to pistols based on years of Hollywood mythology.  To be minimally competent with a pistol requires a lot of range time and constant maintenance practice. Pistol rounds lack the stopping power of both shotguns and rifles and shot placement is much more important.

Shotguns: There are many myths about shotguns in the defensive role.  You shouldn’t depend on the “slide rack” sound to scare bad guys away, you do have to aim and it is feasible for a person to survive a shotgun wound.  That being said, inside of 30 yards the 12 gauge buckshot round is one of the best man stoppers around.  Shotguns require less training than other platforms and cost a whole lot less.  However, due to the recoil, some folks will simply not be able to master shotgun use.  Shotguns also are also very versatile, being good for hunting, pest elimination etc.

Carbines: In my book, the best all around weapon is an intermediate caliber magazine fed military style rifle.  The are handy to use from vehicles and in houses, yet they are easy to hit with at distances that make you think twice about using a pistol. Their major disadvantage is cost. A good, new AR typically costs in the $1k+ range, but AK clones can cost a good bit less.

Battle Rifles: Battle rifles are traditional long barreled semi auto magazine fed rifles in a major caliber (mostly 7.62x51 NATO, but I also include long barreled 5.56 ARs in this category.)  The advantage of a battle rifle is range, and in large caliber versions, penetration of lighter cover.  The disadvantage is handiness and weight.  You can carry twice the ammunition for a 5.56 carbine, and getting in and out of vehicles or moving around inside a house are a pain with a rifle that has a 20” barrel.  There are carbine versions of BRs but it is a compromise,

Curio and Relics: These are rifles that served a military at some point, but are now considered collectors items. Most of these are bolt actions, with the M1 Carbine, M1 Garand and SKS rifles being standouts.  They are generally lower cost than modern semi-auto carbines and battle rifles and there are serious trade offs to performance.  However, given their durability a practiced rifleman with one of these can be a threat as long as they understand their limitations.

Hunting Rifles: These deserve a mention as there are so many available.  Most hunting rifles have a very limited tactical application.  They suffer in comparison to any semi auto weapon inside of 50 yards or so.  The more durable and accurate ones might serve as sniper rifles, but most people have a very limited idea of what sniping requires and the skill set needed. 

22LR: This is a big category of guns and there are many to choose from (both pistols and rifles) I would never recommend these as a primary rifle.  However, one of the primary goals of any shooter should be training new shooters as well as training on your own.  22s provide a friendly and low cost way of doing this.  They also serve for getting small game and eliminating pests.