I finally picked up a decent sized air compressor, so now I'd like to complement it with a few basic tools.  First, what do you need to look for in air tools?  All I would like to get is a good impact wrench and maybe a ratchet.  Also, I wouldn't mind getting a paint sprayer.  What's the difference between a gravity and siphon feed paint sprayer (other than the obvious)?  I would like to pick one up for general painting, maybe small trailers, metal work, or a side panel every now and then (light automotive painting).  I all ready have a sand blasting kit and grinder, but I need a little more.

Thanks!

as with all things, you get what you pay for.

Whats the CFM rating of your compressor? Many Air tool just don't work very well on a low CFM compressor.

I know this is going to sound strange........

Our drain valve at the bottom of our tank is a slow leak, very slow

That allows for the water to settle to the bottom of the tank and drain out every day

Our last setup was air tight and our lines blew visible water through the lines(and tools)

I much prefer the current setup(this is for tools, not painting)

Not sure what the CFM is, but can check once I get home.  What is the minimum needed to run a handheld tool, say an impact wrench?

When it comes to tool, just get a good brand name you recognize. Chicgo Phumatic, Snap-On (if you like to spend big busck), Crasftsman or Ingersoll Rand. For home use, stay with 3/8" or 1/2" impact wrench. Most home compressors will handle this. I have used both types of sprayers and like the downdraft easier to clean up after. The one tool that you did not mention is a sander. They will require a lot of air!. It is due to a constant drain of air unlike other tools that give the compressor time to recover.

As to the drain cock on the bottom of the tank. If you routinenly drain the water from your tank, you should not have much of a problem with water collecting. By having a leak in the air system you are making your compessor work longer and harder and reducing the life span of your compressor - motor, pump, tank, etc... Repair all leaks as soon as you can. It is just lazyness to let your air compessor leak.
No mater what kind of compressor you purchase or have they will squeeze the water out of the the air. Remember basic chemistry for junior high shcool. There are a lot of drains and fitlers you can install on your air lines that will help with the water problem. Also, oil all your tools up when you are using them to reduce the amount of corrosion that the water can cause. I use an inline descicant filter that I replace from time to time.

Quoted: Not sure what the CFM is, but can check once I get home.  What is the minimum needed to run a handheld tool, say an impact wrench?

Cubic Feet per Minute.

It's the volume of air the compressor can supply or the volume a tool will use.

i.e. If your compressor puts out 5.0 CFM then it'll run any tool that uses 5.0 CFM or less with no problem.  If a tool uses more then 5.0 CFM then you'll have problems with it using air faster than your compressor can crank it out.

Also you'll see two CFM ratings, one at 40-45 psi and the other at 85-90 psi.  Check your compressor ratings and buy accordingly.

Yeah, we used to drain the water out of our tank all the time, in fact that was one of MY jobs

The current leak\drip is so slow you can't hear it, it certainly doesn't work the compressor harder