WEIGHT ISSUES ARE ABSOLUTELY KEY FOR ME, because I travel a lot, but equally I need to know that every piece of kit I use is as reliable as it can possibly be.

REBREATHER
I use the APD Inspiration for deeper dives, because it will take me to any depth. The Poseidon Discovery Mk VI is also fantastic. At the moment it has a 40m no-deco depth limit, but Poseidon is looking at developing a deeper, mixed-gas version.
The big benefit of the Mk VI for me is when travelling. When I take the Inspiration we're talking about 30kg including cylinders, but with the Mk VI its 14kg - and with the cylinders off, 9kg. I can put it in my hand baggage!
I can be anywhere in the world, and all I need is a backpack and a wing and I'm away.
The Mk VI is so different from every other rebreather. You have no buoyancy issues, there's nothing for you to do. I've now got my head around this idea that you're totally trusting electronics, and I don't have an issue with it, but I realise that a lot of divers are still saying: I'm not sure.

COMPUTER
I use the Vision on the Inspiration. I love it, its really fantastic. The Mk VI has its own computer as well. But when Im doing open-circuit stuff, I use the VR3. It's robust, I can switch gases, even during the dive, and it can do everything I want it to do - air, nitrox, trimix, closed-circuit or open-circuit.
Most of my open circuit diving is done when I'm teaching, which is about 50% of the time, but my recreational diving is all on rebreather.

REGULATOR
I'm definitely a Poseidon man for regulators. I'm a big fan of the old-fashioned Cyklon. It's so simple that if anything goes wrong, I can actually pull it apart and fix it in the field. I like the Xstream as well. You would need some specialised equipment to fix it in the field, but it's become quite a simple regulator in terms of the first stage.
The beauty about the Poseidons is that they give you a great breathe. They don't suit everybody, and I certainly wouldn't advocate new divers jumping straight into Poseidons, because they take some learning to breathe. They need to be used, too - when they're put away in boxes, they don't store well, though for me thats never an issue.
With all the ANSTI testing and standards that regulators have to meet nowadays, I don't actually think you can buy a bad one. I'm a big fan of Apeks, too, I think it makes a stunning regulator. You can really abuse it and it breathes well.

BC
I tend to be a wing-man. My favourite is an OMS, with 90lb of lift. Even technical divers wouldnt ever need that much, but the nice thing is that I can put my wing and backplate on any system - on a twin-set, a single, a single and pony, or a rebreather.
For me, OMS is belt-and-braces, its worked very well. I'm always looking for something that's robust, can take a bit of a beating, and it does that job.
Another one I've looked at that seems to be working quite nicely is the new Custom Diver.

DRYSUIT
My preference is for membrane suits. The one I use most of the time is a Whites front-entry zip, which is very robust. I dive on average four days a week, and it's a suit that really lasts, and is very good.
My secondary is an Otter Britannic, which is another very good suit.

FINS
I use Force fins, because they're very easy to fit. The manufacturer advises a standard kick when using them, but although I tend to use a frog kick I find them very efficient in getting through the water.
People look at them and think they're a bit odd, but I've been using them for years and they're a great set of fins.

LIGHT
A MetalSub hand-held umbilical is my primary, which is again belt-and-braces, bullet-proof and works really well. I think I had the first MetalSub in the country, 15-plus years ago, and I haven't changed it. It just does everything.
The other make I really like is Kowalski, which is typical German, well-made, hard, robust.
I don't need HID because Im not an underwater photographer, but I need a powerful light and, probably more importantly, burntime. If I'm going to be under water for 2-3 hours, it's nice to have a light thats going to last that long, and not many of them will.
The head's a little large, but I find the light on my Kowalski umbilical just fantastic. It's an expensive piece of kit, at over £1000, but you pay for what you get.
I've also got a little OMS back-up torch that stows away. Small things like that are really important.

MASK
I use a TUSA, for no other reason than that I can drop lenses into it - which is really important, because I'm blind as a bat. I actually have varifocal lenses, with distance at the top and reading at the bottom. It costs a bit more money to do that, but it really helps me out. I went on a dive trip recently and forgot my mask - it was murder!

REELS
What I want from a reel is something that's not too small. I find that these tiny tekkie reels aren't really very efficient. I like one that's got a ratchet on it, and one that, for every turn of the handle, brings a substantial amount of line in.
The reel I'm diving with now is from Kent Tooling. It's heavy, but I don't have a problem with that because it's well made - you can throw it around the boat and it's not going to break.
It's a very substantial reel.

DIVE-BAG
My biggest worry is checking in at the airport. Once I'm checked in, I'm done, but it drives me nuts. My wife says: Do you have to go to the airport three hours before
One of the big issues for me is dive bags. A lot of the ones you see weigh so much. You're trying to get in under 23kg, and the bag itself weighs four or five. Northern Diver has these great big plastic sacks, really cheap. They just roll up and do up, and they weigh a pound, but they're really strong.

OTHER EQUIPMENT
I haven't worn a dive knife for 17 years. The last time I used one, all those years ago, I stabbed a flattie, and when I told my little lad of six what I'd done, he didn't talk to me for about three weeks. And I thought to myself, have I used the knife for anything useful? No, I hadn't.
But I do take snips - they're really important for wreck-divers, because of all the line we come across.
We tend to be up and down shotlines, but for decompression trapeze systems, I'm a big advocate of taking an SMB. I use the AP Valves one with the gas bottle, which makes life a lot easier.
I also carry a small mirror among all the bits and pieces - just to make sure my make-up looks good!