From a shop owner/tech stand point... here is my quick list that I would tell an employee new in the trade asking the same. I usually only recommend they buy Snap-On here if they are going to buy anything because it is the only tool truck that comes by every week. We have no Mac driver, the Matco driver went belly up, and Cornwell driver is flaky (and quite rude these days).
Ratchets - SnapOn. I liked them due to the high tooth count, length, and flex head. Now with the new Harbor Freight ratchets that opinion my change. My techs (and myself as well) have broken every size Snap-On ratchet. They get fixed, but you have to wait until Friday.
Swivel Adapters - Swivel Sockets
Small Turbo Sockets - a lot of selection for up to 10mm headed bolts. So fine in size they are almost "indexing".
Torque Sticks - Buy a 80, 100, and 120ft-lbs set of torque sticks for wheels. Lots of guys use them for axle nuts (alot of GM axle nuts are 100-120ft-lbs). If its a high torque axle nut like a 200ft-lbs, they zip them on with a 120 and finish up with a torque wrench.
Snap-On here has a great deal on Streamlight Flashlights, and he warranties them.
Scan-Tools - if you are going to buy your own, the SnapOn ones have the best converage and the least amount of glitches. Sure the Autel/Launch are good for the price, but glitchy and lack on domestic coverage. Note; ScanTool prices are very negoitable, never pay truck price for one if you can.
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Other then that, I wouldn't buy much off them. In my personal box I have long and short GearWrench standard wrenches, work great and very inexpensive. Never had to warranty one yet.
Gearwrench ratcheting wrenches (its in the name, can't be to bad huh?)
I have a SnapOn box, but also a 44in HF and HF 5 drawer cart. Both are absolutely fine.
HF- Pro screw drivers. HF Prybars with the larger ones being Mayhew.
I still have mostly craftsman sockets from years ago with a few Duralast sockets filling in the missing ones (lost over the years).
I do have SnapOn extensions, but at $140 for 4 extensions in a set, not worth it. My GW and Duralast extensions are perfectly fine and used daily.
Just a short list of the common stuff. We have a lot of Snap-On diagnostic equipment. But the shop (me) buys it, not the Techs.