What chainsets are compatible with a Super record BB from 1981 ?

Rob, I understand what you're going through :-) I started cycling in the mid 70s. I couldn't afford Campag at the time but Shimano had just brought out their Dura Ace range which was quite good but much cheaper. My bike was Dura Ace throughout except for Campag hubs, pedals and headset. And every part you bought then was compatible with everything you already had.

Unlike you, I never stopped cycling so I have evolved along with the bikes. Anyway, to deal with your questions:

Shimano are the brand leaders as their parts are on the majority of off the shelf bikes. Their top of the range is as good as Campag and just as expensive. Sometimes more so. Their bottom of the range stuff is pretty good and reliable. Shimano, are responsible for the current practice to redesign the range and every year and make sure it isn't compatible with the old stuff. Unfortunately, Campag have followed suit.

Your 1980 frame will have incompatibility issues with modern parts in the following areas:

1. Headset. Fortunately, you can still buy 1" threaded headsets
   
2. Brakes. Modern frames use short recessed brake bolts whereas the old frames use longer bolts with those curved washers. You can still buy these washers, but longer brake bolts may be hard to get.
   
3. Rear dropout width is 126mm for 5/6 speed hubs. These use screw on freewheels rather than modern freehubs with cassettes. As long as your hubs are fine, you still get new freewheels.
   
4. Gears. If you are happy to stick with down tube friction shifters then you will have fewer problems. Almost any rear dérailleur will work as the amount of travel with each gear is controlled by you. Shimano introduced 6 speed downtube indexed shifters in the mid 80s. I have no idea if they are still available. Integrated brake/shifters came out later in 7,8,9,10 and 11 speed versions and you'd need the appropriate cassette, chain and mech for each version. And your frame re-spaced if you wanted to use them.
   
5. The bottom bracket is probably the only bit that hasn't changed much (for steel frames, anyway). A modern sealed bearing square taper BB will fit your frame just fine. Shimano do them from about £10. I've bought a nice Tifosi one on eBay for £20. As I said above, any square taper chainset will do, you don't have to spend heaps of money. I have never found any discernible difference between chainsets labelled 8, 9 or 10 speed. I suspect it is just marketing.
   
   

You will have to ask yourself a serious question. Is all this worth it, or should just go out and buy a new bike?