Half a year ago I asked the eternal question: "what should I buy" in this forum. I got a lot of sound advice and learned a lot more as others asked similar questions afterwards. I thought it would be useful for others still in agony over this decision to describe my choice and reasons behind it. That can also give the experts one more chance to prevent me from making a blunder.
First of all, the perfect gear, if such a thing exists, depends on what you want to do with it. For me this means mostly fish portraits and behaviour. Unlike many who live at the two extremes; superwide angle and macro, most of my past shots are in the 30-100mm FF equivalent focal range and 1 to 6 foot distance. I will get wide and macro lenses at some point but for now I will focus my budget and learning at shooting 2" to 2' fish as close as I can get them.
In addition to that I am charmed by the idea of flash-free filter photography, especially for snorkling.
Camera
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From the start I had my eyes on the Canon 20D and that hasn't really changed. The 30D would have been worth the extra money but the housing won't be ready in time so a 20D it will be. For me the biggest selling point over the Nikon D70 is the sensor. Smaller pixels, so higher spatial resolution, and at the same time high ISO with lower noise. The latter is relevant for magick filter shoothing. Apart from that both are stellar cameras and the D70 is cheaper and maybe has an edge in low-light focus. Finally, and completely irrationally, the canon lens line-up is strangely intriguing to me. I'm convinced the Nikon lenses are just as good, they just aren't as sexy. Don't ask me to explain because I don't know the answer.
Housing
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I'm coming from an Ikelite housing for the Canon G2 P&S and have been extremely pleased with it. I get at most two weeks of diving per year and at my current skill level and diving frequency I'm convinced the Ikelite will not limit my enjoyment and success and give me the best bang for the buck. The most annoying thing is the port-chart that is supposed to help you select lenses and corresponding ports. However, many lenses that you think should work are not listed. For others the aperture limits are not mentioned so you're not sure which lens they are talking about. Moreover, after oogling this forum and Ike's pages for 6 months I still have only a very rudimentary idea of how housing, port, lens, and focus/zoom control come together. Expect a detailed expose once I get my kit and figure it all out.
Flash
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This has been a question of IF rather than WHICH. At some point I thought to skip on a flash and focus on filter photography. That would save enough money to buy a really sweet lens. However, I will need a flash down the road anyway and being limited to filter photography is, well, limited. So an Ikelite DS125 is on the shopping list.
Lenses
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Oh the joys, sleepless nights, I-think-I-know-it-now-but-then-maybe-not world of dSLR lens choices. Possibilities are endless, the budget is not, and it is really hard to know how it is going to work underwater until you try. So this is how it has worked out for me.
I really want to get the new 17-55mm f2.8 IS lens but it won't be out until I get back from holidays and I couldn't afford it together with all the other gear right now anyway. I don't want to spend significant bucks on lenses in that focal range because they would be obsolete if I do get the 17-55mm for my next trip.
The broad concensus is that the 60mm F2.8 macro is the best general-purpose lens, good for fish & macro, so that has long be my number one contender and is still in the running. However, the 50mm F1.4 is looking very appealing too. They have a pretty similar and useful focal length for the size of fish I'm hunting and both are said to give razor sharp images. For most F2.8 is plenty fast so the macro is the deciding factor. But for filter photography, and especially trying to push it to greater depth, sucking in as much light for focus and exposure is the name of the game (see my tips and techniques forum message "Magick Numbers"). Unless I change my mind before the weekend it is going to be the 50mm. It's hard to catch damsels, wrasses, parots etc closer than 45cm anyway so I don't think I'll miss the macro terribly and since the 60mm macro is more expensive I can add a closeup lens or 12mm extension ring to get at least somewhat closer (but will loose infinity focus).
I need a zoom lens topside and would at least like to have one UW so I'm not completely in 50mm mode for two weeks. The 28-105 f3.5-4.5 is my current pick. It is cheap but good if stopped down and it covers the longer end of the focal range so it will still be an interesting lens if I get a 17-55mm. It focuses down to 50cm, not great but not bad either for a 105mm max zoom lens. Finally, one person on this forum got shots with this lens that I would be jealous of getting.
I think here my budget runs out. But if I were to stumble upon another $500 then I'd add a 100mm f2.8 macro to the basket to get true macro and a very nice telelens. Alex did some very exciting work in the tele range that would be nice to immitate (actually Herbko also showed some great telepics with a high content of "fish personality" as well). Finally, the limits of flash range for teleshots at moderate distance evaporates when using filters. So perhaps some experimenting along those lines could be of interest.
Ports
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Oh yes, I need ports. All of the lenses I mentioned can be placed behind flat ports. The 28-105 needs the 2.5-3.5" lens port. The 50mm is only 2" but my guestimations show there should be no vignetting, perhaps a slightly positive buoyancy but I expect that can be handled. The extra length will also give me plenty of space to add an extension ring. So the current plan is to stick both lenses into the same port.
Soon to be a lot poorer, yet a lot richer 
Bart
