You know, the thing with a thread like this is that a lot of us just haven't tried a wide variety of things.
I currently own three backplates: An Oxycheq stainless steel, an OMS Aluminum, and a DSS Kydex plate. The stainless steel plate is part of my cold water single tank rig. The aluminum plate is for my cold water doubles, and the Kydex does double duty for single and double tanks when I'm traveling. I began life with a back-inflate BC (after training in a jacket in class) but it didn't fit well, and the day I first put on the backplate, I was hooked. I really don't know if I could be as comfortable and happy in any other kind of setup -- the problem is that I have no desire to try.
I have two sets of regulators, one for single tanks, and one for doubles. My single tank setup is an Aqualung Titan LX with an Apeks octopus, and I love the reg and still feel, after three years, that I got very good advice from my original LDS on purchasing it. It was a middle of the road reg in terms of expense, and has performed beautifully at all recreational depths for me, in cold and warm water. This was a good buying decision.
My doubles regs are Scubapro MK25/S600s, and I adore them, and have not yet encountered anything that breathes better. Even used, they were not cheap.
My fins are Jets; as I worked to propel me, double 85s and an Al80 stage bottle around Cove 2 this afternoon, I gave a silent prayer of thanks for stiff rubber fins. One of the things that is EXTREMELY important to me is the ability to move through a dive site and leave it precisely as I found it, and that requires non-silting kicks. The split fins I started with just aren't good for those kicks; I know, I have had to use them since I switched, and learned it is possible to do all the kicks with them. It just isn't fun.
No account of my gear would be complete without mentioning my absolute favorite piece of dive equipment: My Salvo 21W HID light. Canister lights, by themselves, are enough of an argument to switch to a backplate and harness, at least for anybody who dives in low viz on a regular basis. Can lights are a safety feature, and a communications device, as well as a superb way to find well-camouflaged sea life. Salvo makes superb lights, and beyond that, has customer service that is in the stratosphere (right up there with Deep Sea Supply).
I have three wings -- I have a Deep Sea Supply LCD 30 for cold water, single tank diving, and a Deep Outdoors horseshoe doubles wing, which I adore because it is orange (it's also a nice wing, although I had to take the ridiculously long corrugated hose off it). I have a Deep Sea Supply 17lb tropical wing which I haven't used very much, and ought to play with some more, if I ever go anyplace tropical where I don't dive caves
I have three dry suits. My first suit was a Mobby's trilam, which has some lovely features, including being the only one of my three suits which is truly self-donning. Unfortunately, the suit has leaked almost constantly from one place or another, the whole time I've owned it, which has earned it the sobriquet of "dampsuit". My second suit was a Diving Concepts compressed neoprene suit, which was a nightmare in the buying (a custom suit that totally didn't work, and was replaced at reduced by still significant cost by another custom suit that still was far from ideal). That suit is warm, for sure, but it is not self-donning (and is in fact difficult to get in and out of) and restricted my mobility enough that I really wasn't very happy diving it.
The third suit is a White's Fusion, and I adore the suit. I dove it all winter, despite the mid-40's temperatures, because I simply couldn't face packing myself into the compressed neoprene suit, when I knew how comfortable the Fusion was. I'm going to have to send it back to White's to have the zipper evaluated, because I appear to have gotten a faulty one (as opposed to my husband and a couple of friends, who really don't have issues with theirs) but any mass manufactured product can have its outliers, and I don't blame the company for this, as long as they take care of it for me. The suit rocks.
So does the Mk3 undergarment from White's. This is a superbly designed undergarment, cut to minimize poof where you don't need the extra fabric, but give you mobility where you DO need it (in the shoulders). It's very warm, and remains so when completely soaked, which I unfortunately know. I did 82 minutes in 50 degree water on Monday in this undergarment. AND it has a rear-end relief zipper, for us ladies who really don't enjoy dragging our sleeves in the restroom floor while trying to cope with the results of immersion diuresis
I want an Otter Bay hood, but I don't have one yet.
I have an Aladin Tec 2G computer, which I like a lot. I still miss the display on my Vytec, which was much more old-eyes friendly, but the resettable stopwatch on the Aladin sold me, and the downloading software is MUCH nicer than Suunto's.
My other gear includes a Suunto SK-7 compass in a DSS boot, several assorted spools, a "spreel" (a GREAT gadget), a Halcyon Pathfinder reel (another good gadget), a Halcyon SMB (after trying several other brands), Dive X-tras wetnotes, and an X-scooter.
Too much dive gear, but I really have put together a selection of stuff I really like using. It's taken three years, and way more money than I want to think about, though!