Yay, tool thread... I'm just a hobbyist mechanic but you really cant have just one... so you might as well start with something and go from there...
I really love having a mix air tools and electric...
My 3/8" impact air ratchet gets used so often that I dont think I could ever giving it up after having it... its an Ingersoll Rand brand and I really like them for air tools. I use this a lot for working under the car, for example taking the skid plates on/off.
I bought a Snap-On 1/2" impact a really long time ago, even before all the other popular lithium systems came out... its still the most beast mode impact I own, and it completely demolishes my 1/2 air impact.
There isn't a fastener on my 4Runner that has given me trouble, and 1-2 knocks max and it blasts off lugs. That said, there are cheaper options now, i'm sure most people are not willing to spend what I spent on that impact, but at the time, not really anything on the market that did compete with it either.
That said, a smaller 1/4 drive impact or a 3/8" drive impact is worth having, smaller the better as its easy on the arms and hands with less fatigue and can get into smaller spaces. My 1/2" snap-on is really heavy, and I dont use it unless I really need it, plus it does not fit in really tight spots.
Buy good sockets too, I have complete 1/4" 3/8" and 1/2" drive sets... look at Sunex or grey pneumatic for quality and value.... I have a few impacts sets like this.
https://www.amazon.com/Sunex-3342-8...8&qid=1473889049&sr=8-2&keywords=sunex+impact
My 1/4" white Makita impact has a universal joint with a 10mm in the picture and its makes working on the 4Runner a lot better. Its all about access so if you cant get to it, you cant take it off.
I would like to add a 1/4" drive air ratchet, and a 3/8" drive air or electric impact that is really compact...