Before I talk about the things you need to buy along with your camera to start using it, I want to talk about the lens(es) that may or may not come with the camera. Some of these models have the option of allowing you to purchase it without the kit zoom (for about a $100 cost savings). I want to caution against that unless you already own a kit zoom—which is unlikely since this is your first dSLR.
I wrote an article about purchasing an entry dSLR four years ago. What it so surprising is how much of it has stood the test of time—only small details and features have changed: Nikon autofocus now has more points than Canon (as well as better coverage and the use of color); Olympus no longer is the only company with Live View (even Pentax does it), nor the only company with dust shake (all the others, starting with Canon, now offer it); Sony is not the only company with sensor-shift image stabilization.
Still, the essence is still true: Canon and Nikon remain among the last three holdouts adamantly against sensor-based image stabilization. Canon settings are still bulletproof; Nikon still is light focused: with the best autoexposure system and the best high ISO performance. Olympus and Panasonic are still cramming the coolest tech into the smallest space, Sony is proving their engineering chops, and Pentax is still putting photographic value first.
The advice hasn’t changed: When you buy a first dSLR, it is still the best to forgo the kit lens and plaster on a cheap, fast prime. Lenses still get more expensive, and bodies still get cheaper. Every manufacturer makes a camera for your budget with a negligible price difference…
And the problem is all the cameras are still too good.
In fact, the most significant difference from four years ago is only that the “entry level dSLR” has dropped below $700 for an entire kit, (in addition to) the $1000 “body-only” category—redefining the latter as an “enthusiast” category. Not only that, in many cases, manufacturers have issued multiple models in this sub $700 category, all offering at least one full kit below $550. Three of these sell kits for less than a Canon G11 pocket camera!