Let me ask you 3 questions.
What kind of photography do you want to do? Wideangle or Macro?
Do you think you should have fullframe or crop sensor?
What lenses have you looked at? Cheap kit lenses or expensive high grade L lenses, EF or EF-S, what focal lengths?
The 1st and 2nd are quite related to eachother and the success of the 3rd will be affected by them. This is just SOME of what you need to consider for your DSLR setup and you really do need to plan well if you consider taking a dslr under water..
No offense but I would ignore the above. It's more confusing than useful. Especially since you are just getting into SLR as a beginner.
Question 1 does not affect camera choice. Those questions will dictate your lenses.
Question 2 is what you can afford, not what you 'think' you should have.
Question 3 is three parts.
First, 'cheap' vs L quality lenses is based on what you can afford and if you can actually distinguish the difference in image quality.
Second, EF-S vs EF is a format thing. EF-S are not backwards compatible with all cameras. They were designed special for crop cameras. EF lenses are backwards compatible with crop or full frame cameras. If you plan to move to full frame, keep that in mind before you invest heavily in a bunch of EF-S lenses. There is also a new STM format out, not sure the compatibility on those.
Third, you won't know what focal lengths you need until you start shooting.
Overall, get the kit lens first. It's cheap and works great for the price. When you outgrow it or decide what you want to do, get more.
---------- Post added August 11th, 2013 at 08:30 PM ----------
While I would *like* to shoot macro, most of the time I'm shooting larger subjects like turtles and such. It isn't very often that I have the chance to shoot macro subjects.
I had not considered the sensor type but after doing some reading I see how the sensor type can impact your selector of lenses but I'm far from being in a position to decide that yet.
Like I said before, I was looking to buy a dSLR now (near future) to work with on land and then as budget and experience allows (months? maybe a year?) work my way to a underwater setup.
From what I can tell, getting into underwater photography will likely cost as much as your camera and lenses combined, or more.
If you are just wanting to learn about and get experience with SLRs, I suggest the t3i for photos only or the t4i if you might do video too.