After some comments I thought this would be an interesting thread to start.

What tools do you use? Fill in below

1. Oldest tool

Unfortunately I had to leave it in ZA, will fetch it on my next trip there; my first set of screw drivers I got when I was a kid.

2. Most useful tool

Side cutter, cuts everything from wires, to paper, to making that stupid small hole in the plastic thingy that goes over the wire thingy a bit bigger.

3. Newest tool

Heat Gun, got tired of burning my fingers with a lighter trying to shrink heat shrink; now I can cook them with great efficiency.

5. Best tool gotten for free

Weller digital temp controlled soldering iron; thou work might ask for it back someday…

5. Next tool

Soldering/Hot-air Rework combo station; want to start doing surface mount boards.

6. Misc

Multimeter, most useful tool after a side cutter.

I'd say that screwdrivers — for me — are the most-used tools. I tend to aim to build things from modules, so mostly it's  bolt-together jobbing.

OK, there's *some* soldering of board headers when not done at the factory, but even wiring and cables are either purchased or crimp jobs.

To answer some of Adi's headings, my oldest tool is a great blade screwdriver made in the 1930s as  part of my Dad's fitter-and-turning training. You don't tend to see them these days — huge bulb handle and a 10 mm blade. Absolutely a must for unscrewing doors (when even an electronic screwdriver can't budge the screw, since it's typically  been painted-in and allowed to settled in for 40-50 years). 

Still on screwdrivers, a good old 1/4" phillips-head is probably the most-used bolting-together tool, with some of the 1 mm and smaller phillips heads or "other" (e.g. things to open up PDA's) comming a close second.

Still on screwdrivers, one of the newest tools (actually bought after the Dremel is a cheap high-torque electric screwdriver. I've been throwing together flatpack shelving and cabinets lately, and this little item has saved me a lot of wrist-pain.

The absolutely newest tools are a surplus drill-press and metal folder/cutting table from a local engineering shop. After some initial teething problems, the drill has started working properly, and even the metal cutting (1/8" mild steel up to 6 ft long) is performing like the seller told me it did when they first bought it. 

I'm not much into soldering irons, and after burning up an old and expensive temp-controlled iron, and a more modern 4w-er, I'm presently down to just a 1w basic 240v iron with an ultra-fine point. I've managed to do most things with this, after a bit of re-training of reflexes. (The first few fine jobs were QUITE a mess).

I have a slew of old "analog" multimeters and a couple of 10-20 yo digital ones, but have never seen a need for a scope. But I may weaken at get a cheap pocket scope in kit form, if I have much more trouble with some of these embedded boards I'm trying to stitch together.

The most useless tool I ever bought was a "quality" wire-stripper. Sure… it worked OK for the first 5-10 years, but then completed screwed itself up! Luckily I still have a large supply of 1960s  1-edged razor blades (you know, from the time before they deliberately blunted them down in the factory for "marketing reasons" — well… that's MY theory, anyway .

Standing in for crimping and nibbling tools of various kinds are cheap $1/2 Chinese side cutters I tend to get by the dozen. You chew up something too tough for the poor thing? Into the bin, and onto the next one. By this time the  plastic grips on the old cutter have about dissolved from persiration, elbow-grease and high-volume swearing, anyway. 

Does swearing abuse at tools and inamimate objects count as a tool? If so, I may have to re-work my list ordering… 

I got a cheap one on ebay, sub $150, and it cannot sample half as fast as claimed, the samples are extremely noisy, was a waste of money. Will be a long time before I look at USB scopes again. I am probably spoiled from using a Tektronix TDS1012 from work.