Thanks for the great advice I've received so far on this site!
Ok, next question: Aquatica, Sea & Sea or Subal? (I have been steered away from the Ikelite by many people.) I used a Sea & Sea with my Canon 40D during my first course and it worked great--no complaints. Is this just a matter of personal preference? I understand the Subal is more expensive? As I'll be having this for the foreseeable future, it's important that I get it right.
Also, should I be looking to get a second 40D while they still make them, or am I better off going with two more advanced models (e.g. 50D)?
Thanks so much in advance for the help!