Kimber Pepper Blaster II

I really like these clever little things. I think it was a good design change to make it easier to point and aim via the abbreviated grip and solid sights. It's still flat and light, and works with the same reliable pyrotechnics, giving you two shots. The translucent red plastic case will help to keep people from mistaking it for a projectile-launching firearm, and at the same time, gives it an interesting cyberpunk look. It is snag-free and easy to manipulate.13 foot range with a blast of pepper that travels at 90mph. Two barrels, over-under configuration.
No, it's not a force field or a sleep-ray but it is useful. Think of it as a very clever way of throwing sand in someone's eyes. It gives you time and options. Two things you might need. Some people reject devices like this because they aren't big-bore firearms. Some people reject them because they think anything other than a phone call to the police is the equivalent of vigilante justice. Both ways of thinking are well beyond silly and indicate psychological hang-ups that should be addressed on a personal basis.

Mace Pepper Gun

This is a very useful niche-filling device. I carry one of these every day. It is reloadable, easy to use, easy to carry in pocket or in a holster (also pictured). It has a metal alloy-frame, lacks obnoxious protrusions, and doesn't weigh too much.

The ergonomics are similar to a small-framed revolver and in fact, the safety is located where the hammer would be on an actual revolver -- just pull back to fire. The stream of pepper spray looks like it's coming from a super-soaker. You can hold the trigger down for one long stream, or use it in several shorter blasts. It has very good range, about 25 feet.

There is an LED light built into the device at the top of the trigger-guard front. Taking up the slack on the trigger activates the light. This may cause your assailant to lose his night vision or focus in on it just in time to receive a healthy dose of pepper spray. We have a good deal on it here. I enthusiastically recommend this item and use it myself. You can quietly acquire your grip while it is still pocketed and be ready when things go sour.

Techno-retro

A nice walking stick could be what you need. Made by the kind folks at Cold Steel, this nice-looking Irish walking stick is actually made of crazy-tough synthetics. Good for a stroll and for convincing people to leave you alone. Impact weapons are intuitive and effective.

Small and simple

If you're not unfamiliar with striking, and would like a little mechanical advantage, get the Stinger. Adds rigidity to your fist while focusing your striking energy into one small point. This is advantageous for a number of reasons. Not a great endeavor to carry, it's very small, weighs close to nothing. Sometimes it's good to keep it simple.

Subtle Stun Gun

Pepper Pager

Ah, the Pepper Pager. It brings to mind stale spy movies with quirky props and yet it's a very good idea. It's a hide-in-plain-sight type of device, with the shape and size of a pager or battery pack. It contains two separate spray reservoirs and two separate emitters. Roughly a twelve foot range. Those with the temperament or inclination could use it as a fist-load. A personal protection item that doesn't draw unwanted attention to you could be a useful thing.

Mace Night Defender

 This is a very simple and affordable item. It's a good choice for those who for various reasons, want to avoid "gun-shaped things." The Mace Night Defender has the shape and handling characteristics of the common thumb-actuated pepper spray canister but adds a bright LED light above the spray emitter. I like that for much of the same reasons I like the LED on the pepper gun. The Night Defender can be palmed and carried without causing a general stampede and brought into use quickly. Flipping up the thumb trigger cover activates the light. Good deal on a good tool from a great company. It offers an18 foot range without being too large and bulky.