I've been buying tools for a long time. In that time, there has been a very slow, but steady advancement in the tools available to individuals, and looking back, it's nothing short of a revolution in capability.
Here's a few, that were the top of my list when I bought them -
1. Black and Decker Workmate - introduced in the 1970's - I bought my first one in about 1980. Up to then you had to do everything on a workbench.
2. HP11C and HP12C calculators. New in 1981 - the 12c is still sold in the exact same model. They tried to upgrade it, and people still bought the old one.. Think about that - an electronic device that is the same in 2011 that it was in 1981! - name just one more... The 11C got me through engineering school. The 12C got me through business school.
3. Sony Walkman - about 1982. Up to that point, there wasn't such a thing as a small handheld, high quality music device. I remember the feeling of listening to that unbelievable sound quality for the first time. This single device made doing mechanical work much less of a boring job.
4. My first Leatherman - this was such an improvement over the pocketknife I had been carrying up to that point.
5. Panasonic Cordless drill - about 1991 - was the finest cordless drill made, and that drill is probably still better than many of them sold today. I replaced it with an upgraded model in 1999, and I wish I still had them both.
6. The Internet. In 5 minutes I can find out how to fix most anything - whether I know much about it or not.
7. SK 1/4 and 3/8 socket sets in the green case. I had sockets before, but the case keeps these great tools so well organized that my sets work as well today as it did 12 years ago.
8. CNC machines. The company I started my career with was full of $100,000 and up NC machines - they're all junk now. The latest crop of cheaper homeowner based CNC machines are bringing the same capability to your basement.
9. Mig welders. In the 1980's a welder was a big machine that weighed 800 lbs.
10. Milwaukee V28 cordless. Even though my Panasonic Drill was still my favorite after about 15 years, 12Volts or even 18volts isn't enough to replace a corded tool. Enter Milwaukee V28's, which I bought in 2008, and I've rarely used my corded tools since.
11. Surefire type flashlight - In the 80's a maglight was the ultimate. Somewhere in the early 2000's, I found the Surefire G2 - all my maglights were instantly obsolete. Recently, these all went to LED bulbs, and they are even better.
12. Jawhorse - I can't believe it's as good as it is. It replaced my B&D workmate.
6. Tire balancer and changer - seemed like complete overkill to own one, but it's so nice to have them, so I'm not relying anybody else.