Thanks again to all who are responding. Maybe these forums are not as intimidating as I thought.
I have never for a moment forgotten what I love so much about diving and am still more comfortable underwater than I am on land, but I've a long way to go getting back to the cutting edge on all the new gear.
You love being underwater, you'll do fine here! If you like gear, we'll talk it as long as you like! This forum has manufacturers, instructors, technicians, researchers and passionate users all happy to discuss anything. I'm new here myself and it still amazes me the depth of knowledge represented and freely offered. I for one am looking forward to hearing your thoughts on 'modern' diving as you can contrast it to the sort of class materials and equipment you were offering students in the 80s.
Here's a few thoughts, not intended to be complete or in any way exhaustive. I just happen to be awake with the remnants of a flu and am typing until I can sleep. Hope some of it is useful.
The BCD comes in 3 main flavour now. Wing / backplate (around for decades but recently popular on this forum) the jacket style BCD (most common and I'm sure you've dove one?) and a bladder / harness configuration (diving with side mounted tanks)
Dive computers are in two flavors. Recreational and technical. Increasingly those lines are blurred. Still tables inside. A few different tables being used and interesting research is ongoing on decompression theory. This research gets more practical once you're beyond recreational depths.
Fins. Tons of marketing, not much has changed otherwise . I'll give a nod to force fins as I know divers who find them helpful for joint issues.
Regs. Endless options. A few basic designs with various slight variations. Lots of marketing once again.
Wetsuits. More flexible materials available now. The neoprene isn't so difficult to get into in some cases. Perhaps the comfortable neoprene was available earlier but didn't reach my neck of the woods?
Masks. A trend toward smaller mask volumes. Slight improvements in comfort according to some. Vast selection allowing for a better fit for the face.
Dive knives. Smaller. Specific purpose. Rarely do we see a BFK (can't post the meaning of that acronym) in most dive contexts. Trauma shears are also useful tools underwater.
Hose materials. There are more flexible hoses available, they have a recommended shorter service life but some added comfort gained. Standard rubber industrial hoses are still the standard.
Tanks. Hmm. Depends on the area. Similar selection off hand compared to what you'd be use to. There is a perceived popularity for side mount diving where (as the name suggests) the tanks dangle closely beside the diver instead of the back.
New certifications. Perhaps it's marketing, perhaps it's a more effective learning strategy, perhaps it's that we like to feel we are continuing to progress. There's a few new specialties, nothing special. Technical diving history I won't speak on, my impression is it's been developed much since the 80s with safer practices and equipment configurations. Excellent courses available from instructors who have been active since you were teaching yourself. Some on this forum. I suspect you'd enjoy learning from them.
Boyancy. A little wishful thinking on my part, but the concept of being able to neither float or sink during every part of a normal dive is a foundation to good diving. We don't crash into the reef or swim along almost vertical finning to stay in the position in the water we want.
Environment... More emphasis on not touching pretty things? (I don't know what to say here)
Mixed gasses. Deep air isn't considered safe for the majority of divers and new researcher is suggesting helium could be added to the mix as a more suitable breathing gas in a meaningful way as shallow as 100ft even. Most people (dangerous generalization please don't hang me) consider it needed for dives deeper than 165ft or a little shallower. The high cost makes helium mixes fairly uncommon still in.
Rebreathers. I personally love the silence and extended bottom times they facilitate. The concept is simple. The refinements are ongoing and there are a ton of popular units for sale. Each has it's own set of design strong points and fan club. Picking which ones to dive can be challenging but it's often popular to test several units and get to know the designs before committing to investing in one.
Underwater scooters. For longer dives, caves and shore diving the diver propulsion device has improved significantly with the development of better battery and motor technology.
Dive lights. Smaller more powerful. Again thanks to technology improvements.
Agencies. Still a ton and all feeling they are superior in one way or the other. You'll run into fanatics pushing their personal flavor just like in any sport or hobby... Or religion for that matter.
OK, I'm sleepy now. I may edit this into oblivion when I awake, hope a few things said are helpful.
Anyway, welcome once again.
Cameron