I've sold compressors for years, many makes and sizes and the tools that they support.
The first thing you want to do is decide what you want to do with the unit.
Then look into the tools you want to use and can afford. All tools use different amounts of air volume. A tool will require XX CFM ( cubic feet per minute ) at XX psi ( pounds per square inch ) and a general rule of thumb is to buy a compressor with at least 10% over what you need. When you shop for tools, buy carefully and shop for tools that run efficiently on smaller compressors. I have seen some tools that look identical yet one runs on 4 or 5 CFM and the other 15 cfm. Shop carefully for the most efficient tools in your budget.
Oil bath compressors last longer but require a little more maintenance, due to the oil in the pumps that needs to be changed periodically. They generally turn slower than oil free compressors, giving them more longevity due to less wear.
Oil-less compressors usually are cheaper but deffinitely make more noise, pound for pound. They need to turn faster to make up for the lack of oil in them which creates a better seal.
Most of what you will look at in the $200-$300 range will be oil-free and good for small tools that work in bursts.
Your sand/media blasters will not work effectively with small tanked units due to the volume of air ( CFM's ) not being able to be replenished by the pump at the PSI you're going to want to run.
You've got a shot at finding an effeicient blast cabinet if you get a medium sized compressor. Know the bigger the blast media , the bigger the tips , the bigger the CFM's you're gonna need to support it.
CFM's drop as you raise pressures nonormally. You'll see ratings at 40psi and 90PSI listed on the tanks usually and note the CFM's are less as you raise your pressure.
Most paint spraying equipment will run at 40psi. You may be able to get a detail gun ( a small spray gun ) for your duracoat work and have no problem. Once you start looking at better and bigger guns for larger volume material application, like painting a car or similar stuff, you get into more CFM's.
On painting......
Generally there are two kinds of paint systems ( keeping this simple so you have an idea ).
An airless sprayer, used my professionals to paint homes, inside and out, is more like a paint pump. It's going to deliver paint to the area with less over-spray than an air sprayer. The finish will not be as good ( meaning it will not look like a Porsche paint job ) but coverage is good and no compressor is needed.
Air sprayers , usually used for automotive and other finer finishes are very different. They mix the paint with the compressed air, producing a much finer mist if you can understand that. That translates into a finer finish.
Think of this........
Take a bottle of windex and spray it at a table. You get an area of the table wet. That's airless.
Take a can of hairspray now. Spray it at the same table. You'll get a big area of the table wet, you'll most likely get some on the chair, some on the dog on the floor, someone in the next room will yell "who the hell is using all that hairspray", and so on. The hairspray is atomized with a propellant ( like paint and compressed air ) to get it to it's target, but it's not as controlled.
Bottom line??? Don't bother thinking about using a compressor to paint anything in your house, on your house or near your house unless you want overspray on everything not covered up completely. Invest in an airless sprayer if you must do this stuff and use your compressor for the other stuff.
Let me know if you have any questions and sorry for the long post. Hope this helps.