Early Retirement Extreme Forums

I am in the market for an Air Compressor to power tools, pump tires, etc. I want to buy one quality compressor and use it for everything for a long time. I'm not sure what size / pressure will be right for me.
My FIL has a 33 gallon and a 3 gallon. The 33 gallon never gets used and the 3 gallon gets used a lot because it is light and convenient to move (wheels). I was thinking about getting something in the 2 - 6 gallon range rated for ~125 PSI. Any suggestions about brands or things to avoid?

You'll probably want a 6 gallon compressor. It's still very portable, but you can use it for longer and it generally has more pressure. The best way to purchase a compressor is to find out how much pressure and volume the tool you might use need. Then find a compressor that has slightly more.
Oil-less are easier to maintain and less messy, but have less lifespan than oiled compressors. How often will you be using it? What tools do you want to run with it?

My short term plans are to use in conjunction with a 16ga nailer for trim work. I also want to use it for car tire pressure.
My long term plans include picking up a framing nailer and framing/finishing the basement.
I basically don't want to buy a compressor and find out later that I need a new/different one.

As Mirwen said, a 6 gallon (on wheels) is a good compromise.
Smaller than that and many tools (impact wrench, spraygun, nibbler, air chisel, sander) will kill the reserve.
On the other hand, if you're not going to own/borrow those tools, then there's no point in having more capacity. If all you envision is using the nailer and inflating car tires, then get the 3 gallon.

Thanks for the responses. I think I'll stick with a 6 on wheels.
For my own edification:
What would you need a 10+ gallon air compressor for? 30+? 60+?

What practical benefit is there between a 100 PSI and 150 PSI air compressor?
My take: P and V are linearly related for an ideal gas. So, it seems that a 6 gallon at 100 PSI would provide the same pneumatic power as a 4 gallon at 150 PSI. Obviously this decreases the weight/size of the compressor, but it seems like a machine rated at 150 PSI would be higher quality (and perhaps quicker/quieter). Anyone have any experience in this?
In case you are wondering, I am asking here because I feel air compressor advice on the internet is mediocre. In general, it seems like advice is "higher = better". In particular, for example, ( http://www.aircompressorsdirect.com/sto ... essor.html ) contradicts their own advice, giving the "BEST" rating to a belt driven model. They also give the top rating to this compressor ( http://www.aircompressorsdirect.com/Cam ... /p746.html ), although it has only received 1 star reviews apart from their 5 star. [To be fair, on Lowes, it is 3.7 / 5.]

I have a six gallon wheel model form SAMS.
Adequate for me and as I recall in my research the ideal size compressor will run no more than 50% of the time you are using it.
I.E.:if you are using it for a solid hour it should run no more than 30 minutes during that hour yet maintain the correct pressure.
Explained to me as allowing the compressor to cool...compressing air releases heat not just from the act of compressing but from the air being compressed...thats why when air is quickly released through a nozzle you may actually see the nozzle form ice on the outside as the expanding air extracts heat from it.
Same is somewhat true for a well pump and tank....a regular faucett should run for 60 seconds before the pump motor actuates to refill the tank and maintain pressure...any shorter time and your well pressure tank is too small..

It's kind of a mix between pressure, flow rate, and tank capacity. Like @FrugalZen said - the tank capacity is the buffer that keeps the motor from running constantly, and can allow you limited operation at flow rates higher than your pump capacity. Not good for the compressor if you're operating a commercial garage... but if you use it twice a year to change your tires, it can probably handle a little extra runtime while you wait for it to recharge the tank for your (otherwise too hungry) impact gun.
Most tools have stated requirements of a certain CFM flow rate at a certain pressure. So find the type of tools you might use, and make sure you have enough. If you'r going to open a garage, then overshoot and get a big tank too.... if you're just going to use it a couple times a year, you can get away with less. Usually blowing or rotating (air blowing over vanes) tools use the most. Nailers not so much. You're not going to run a sandblaster off a 3 gallon 1/2 hp compressor.
Higher pressure can get you more force out of certain tools (impact guns, air hammers, etc). It can also get you a little more runtime out of a given tank if operating/regulated to a lower pressure (100psi regulator off a 150psi tank will run longer than off the same size 100psi tank - as you alluded to).

I'd once heard that the oiled compressors are quieter than the oil-less compressors, all other things being equal. Is there any truth to that?