Protective Equipment and ClothingI wear protective glasses all the time in my shop, I do this because I kept finding myself working without the glasses on simply because I forgot - this is of course pretty dangerous. I shopped around for a while and found some very comfortable glasses which are ventilated.
Whenever you work with something noisy, such as a grinder or wire wheel you should wear hearing protection. I prefer the ear muffs over the little foam cones which go in your ear - they annoy me and distract me from what I'm working on.
Even when it is very hot I always wear full length sleeve overalls and work boots in the shop. I've lost count of how many times these have saved me from injury.
When welding, use the safety gear. I found the standard smoked glass to detrimental to my welding as I could not see the work well (if at all). I found a gold leaf glass which replaces the smoked glass. Now I see the work clearly as long as it is well lit. You could go further and buy some of the electronic goggles which are clear until the weld starts when they darken. I keep my ear muffs on when using the Mig as I've found that without them my ears ring a little after doing long jobs such as seam welding. I use full length leather gauntlets to protect my hands.
I have hurt my hearing a little using loud tools and regret it whenever it is quiet around me and I get to listen to the ringing. Fortunately I changed my way before it got too bad and it only affects me a little. Never use loud tools without protection.
ElectricalIn my shop I have installed a dedicated circuit which has circuit breaker and a TSD (an Earth Leakage Detector). The TSD detects when there is an unequal current going into the circuit than out of it. This indicates an earth leakage which could be a short to the case of say a drill, or it could be you being electricuted when you cut through a cord on your bench. In any case it cuts off the power about 30ms after it detects the imbalance.
I do not have enough electrical outlets in my shop which means I have a dependancy on power boards (strips) and extension cords. This decreases electrical safety in my shop by exposing some of the wiring to chemical and mechanical damage.
Pay attention to how much load you are putting on a circuit. Any one outlet in Australia can supply 10 Amps and in general the wiring will be gauged to deliver a maximum of 32 Amps probably with a 20 Amp breaker. Don't depend on the breaker saving you - if you load a single outlet up to 20 Amps the breaker will not blow, but you might get an arc inside the plug causing a fire (note that the TSD will not "see" this).
Consider placing red "mushroom" power off buttons around the shop. These are large buttons which can be belted to kill the power.
MechanicalOne of my friends used to have a pony tail until he visited my shop. While using the drill press he got tangled up and just about had it ripped off. Fortunately he managed to kill the press before he got badly hurt. It did convince him to cut it off though :)... There is a simple moral here - if you have long hair cover it up and don't wear loose clothing.
Most of my equipment is hold and does not have safety guards so I have to pay extra attention when working. I'm always careful to give a quick run down of the machine to any visitor who is going to use it.