Well, right about now I'd advise against getting an Ikelite strobe or electronics. I recently got a D300 in an Aquatica housing, and stayed with Ikelite strobes because I already had one DS125 from my old system. Well, one pool dive and 4 ocean dives and I had to send both strobes, the TTL converter and the dual sync cord in to Ikelite. They told me the TTL converter had leaked, a wire was broken in the sync cord, and my old strobe needed a new battery and rebuild (okay, it was three years old, so that wasn't too bad). I've lost two other sync cords on my last system and had to send the strobe in once.
Now I'm in Cabo and ready to get on a live-aboard in just over a day, and one of the new battery packs just broke. I've had so many problems with Ikelite electronics I wish I'd gone a different route, but I can't afford to for now. When they work, they are very nice, but man have I ever had a lot of problems. No complaints about the housing though.
For a lens, get the Sigma 17-70 HSM. It is a wonderful lens and I'm really enjoying using it underwater. I sort of wish I hadn't bought the macro port yet, because the 17-70 fits in the dome port, and it is long enough to suit me for now. But if you want serious macro, this lens isn't long enough. If you are trying to spend a bit now, and more later, perhaps by a dome port and a lens like the Sigma, and get wet and see how you like it.
Greg