I'm just going to cut and paste something that I posted elsewhere:
There's little danger in buying used or refurbished equipment from the big suppliers like
B&H Photo Video,
Adorama or
KEH.
Depending on your budget, a used Canon
EOS Rebel XSi (aka EOS 450D outside North America) wouldn't be a bad place to start. Add the
EF-S 18-55mm f/3.5-5.6 IS wide-normal kit lens and a memory card and you're on your way. Add the
EF 50mm f/1.8 II to play with shallow depth of field (e.g.: portraits and indoor non-flash photography), the
EF-S 55-250mm f/4-5.6 IS telephoto zoom to bring small distant objects closer and a
Speedlite 430EX II (or an old Speedlite 420EX) to round out a very versatile but still inexpensive kit.
You could use the
Canon loyalty program to get a refurbished camera and lens for a very appealing price directly from Canon. The
Rebel T1i + 18-55mm kit lens for $480+tax is a great deal, for example. Buying used gear from the sources above is fine. Your local Craigslist may also be okay. You can track the new prices of these and other gear at
cpw. You can also shop the usual on-line deal sites like
Slickdeals to find when good deals are available (like Amazon bundling the 55-250mm lens with a
Rebel T2i kit for under $900).
Having said all of that, the Noinks would tell you not to buy anything but a Nikon. I like Nikon's mid-range (D90 or better) and top-end cameras, but I consider the Canon line to offer a better value at the entry level. It's like Ford vs. Chevy with some folks. The truth is that despite the vigorous debate over gear, it's the work of the photographer that makes the difference in results. It is a poor craftsman who blames his tools. Even the entry-level DSLRs available today are much better than the gear that Ansel Adams had to work with. If you have friends or family who are already invested in one of the major systems (Canon, Nikon, Sony, Pentax, micro-4/3, etc.), the ability to borrow lenses, flashes, etc. could be a deciding factor in choosing which system will work best for you.