I think if you get a chance to "fondle" the Ikelite, Aquatica and Nauticam housings, the difference in price is easy to understand. I have the Aquatica AD7000 (AD90 previously) and it is an absolutely superb piece of kit. I am not overy familiar with the Nauti, but a friend uses one and it's also a quality piece of gear.
Not to take away from the Ikelite too much, but if the budget allows, I think you'll be much happier with one of the others. Apart from ergonomics, the Ikelite is also mach larger and boxier. It does have the advantage of being able to visually check seals and being able to see "inside" for water, but then they take short cuts like a pretty rinky-dinky port lock. I know of two people personally who have flooded Ikelite's when entering the water when the dome simply fell off...
I chose the Aquatica over Nauticam largely because there isn't any retailers near me where I could see them. Aquatica is in Montreal which is about 6 hours from here so I had the pleasure of visiting their plant and getting to know the owners and staff and learning about how the housings are made first-hand. Had I seen Nauticam as easily, I might well have gone that route too...
Back to your original question, I use the Tokina 10 - 17 for wrecks and landscapes, and the 60 macro for portraits and uncooperative larger stuff (like sharks that won't come too close). I also have a 105 macro which is great but tough to focus unless you are planted firmly on the bottom. On the cropped sensor, it's behaving like a 160 mm lens or so and DoF is really tight. You really need to play with your aperture to get the look you want. You'll also need a flat port, some extension rings possibly and a dome port too. Focus and zoom rings also, depending on the lens/port combo you end up with. I use the 8" acrylic dome. I'd love to own a larger glass dome, but if you need to trim a little, that's one area you might. Aquatica has some neat mini domes as well that are supposed to be very good, but are somewhat lens-specific.
Getting back to Ikelite again, while I am not a huge fan of their housings, I love their strobes. I use two DS 161's and they have worked flawlessly. I still have some old Substrobe 225s that are 20-25 years old and they still work... Just not on digital cameras. Using these strobes with an Ikelite housing does allow for TTL metering, but I have yet to meet a successful photographer that shoots TTL.
Also, if you aren't in a huge panic, keep an eye on the classifieds here and on Wetpixel. Housings for D7000s already come up now and again and some folks have moved up to the D800. I bought my D90 housing that way, and saved a fortune. You just need to figure out a way to confirm it's in great shape before you buy...