Toolboy:
I got my D90 in May 2009, moving up from a couple of years with a D70 (after fighting the digital urge for many years). I really like the D90. The rear screen is outstanding - much easier to review the image and make adjustments. Focus control is better than any autofocus camera I've used - better reaction time and more reliable (that said, I end up on manual focus a lot). The info button (displays all camera settings on rear screen) is one of my favorite features of the camera. The viewfinder is clearer than the D70 - I am able to see critical focus before firing - and any other camera I've used since my Canon F1/Speedfinder days. The camera has more features than I'll ever use, but it has been fun learning the camera.
On Ikelite... I do have my D90 in an Ike housing. That was largely due to the investment in ports and cords. I've had Ike housings since the early 70's, from an Instamatic housing to a series of SLR housings. One aspect of Ike housings that I haven't liked over the years is the stack-up of slop in the plastic gears. Back in the day... when we had focus, aperture, and sometimes zoom to deal with, there were a lot of gears that had to work properly to allow shooting. Gear mesh started loose and would either get sloppy, allowing the gears to slip, or get tight, preventing gears from turning as you went deeper with the housing. This has improved greatly with new housing designs (stiffer) and the reduced number of gears needed. That said, I do still have trouble with the force required to rotate zoom lenses and have occasionally had the gear jump.
I did migrate to an Aquatica housing a number of years ago (for a Nikon 8008s) and I loved the tightness of the controls - especially the gears for aperture and zoom control. However, what I really missed with the Aluminum housing was the ability to see the camera. Especially now with all of the buttons on modern digitial cameras, I simply like being able to see the camera in the Ike housing. I played around with an Aquatica housing for the D90 (topside only) and they are doing a much better job of labeling the controls, but it still doesn't compare with being able to see the camera. That and I'm Slovenian... meaning not so much cheap as miserly when it comes to throwing away money for no percieved value. Based on all of that and Ikelite's reputation for great customer service, I do recommend the Ikelite housing. Sure, I'd like a fancier housing, but not for the price.
On strobes, I have a pair of Ike DS-125s. Can't offer any comparison to other brands as Ike's are about all I've had since SubSea Strobes went off the market (other than a brief foray with a pair of MCDs which I still use on occasion). Others have complained about battery life, but I think its great. I have 3 batteries for 2 strobes. On a trip, I keep one on charge all the time and rotate on a regular basis throughout the trip. I try to start the day with a full charge in both strobes and rarely go on a night dive with out both fully charged. I've run out of battery life only a couple of times and it has been my fault each time - either missed a rotation or swapped the wrong battery.
Flip side of that is the weight - they are heavy strobes. My SubSea may have been heavier on land, but with more displacement was lighter underwater. I ended up buying a pair of ULCS 10" buoyancy strobe arms to reduce wrist fatigue - they helped.
Lots of opinions - hope it helps. Good luck in your quest!
