The best first lens you can buy (many photographers agree with me on this).
(COMING SOON) ...My recommendations on how to use your camera when starting out, and what to get familiar with.
(COMING SOON) ...Some flashes suck, and some are amazing. Most people start by using flash in the worst possible way. Here's my tips on starting off using flash.
The camera companies, and often sales people, use megapixels (millions of pixels) as a selling feature. That's just the resolution of the sensor and is only ONE metric of image quality. Other qualities such as dynamic range and low light performance are generally more important. Even more important that these is the practical features of the camera. For example, a touch screen is more useful for most people than 50 megapixels is.
You actually should figure out which lenses you are going to get before you decide on a camera because your lenses are more important than your camera. Most people buying their first real camera focus most of their decision on the camera when actually the decision should be more heavily weighted on the lenses. Which brings us to the next tip...
The kit zoom lens that comes packaged with lower-end SLRs like the Canon Rebel, is not going to get you the professional-looking results you want. (If you buy a higher-end camera that comes packaged with a 24-105 f4, that's a different story because that is actually a good lens.)
My recommendation (and many photographers agree with me on this one): get "body only" and buy a 50mm f1.8 lens. Photographers often call it the "nifty fifty" because they are relatively cheap to make and you can get professional-looking results with this lens. Canon, Nikon, and Sony all have one of these. It's Canon's cheapest full-frame lens at around $180 Canadian, Nikon's is around $250, and the Sony is around $300. (Caveat: All 3 have autofocus but be aware they are not truly weather sealed - the Nikon has some weather resistance.)
Why 50mm f1.8? The perspective provided by a 50mm lens on a full-frame camera has a very natural feel to it, it's similar to the perspective we see with our eyes, making composition relatively easy. The wide f1.8 aperture lets in lots of light so we can use it in casual, low-light situations such as in restaurants, as well as causal shots at weddings.
50mm seems to be the sweet spot as far as manufacturing costs, because if you get a wider lens (like a 35mm), it is typically more expensive, and much wider is much more expensive; longer (more telephoto) also gets more expensive. So 50mm is the sweet spot as far as getting a good lens that can produce professional results for pretty cheap. I know someone who has shot for several years with only a 50mm f1.8, with excellent results.
Don't use the strap your camera came with - it's uncomfortable to have the camera bouncing around on your chest and as a result you will not often take your camera with you. Find a solution that's comfortable for you. Black Rapid straps are great if you are not concerned about your camera accidentally banging into something once in a while (I have been using a Black Rapid strap for many years and my camera and lenses are still practically mint but I once met a photographer using Black Rapid seven days a week and her cameras were very scratched up so maybe it depends how reckless you are, but for me it’s a non-issue and I love the Black Rapid because it’s the fastest way to be get ready for a shot). Another great option is a camera bag that opens from the top: a top-loader. You sling it over your shoulder, and pull out the camera when needed. A sling-bag is another option. Your local camera store should be able to help you pick out an option that works for you. Don't attach that cheap strap that your camera came with.
I am always surprised how many people people have decent gear and don't use it. Learn how to use your gear. Then always be ready to capture the moment. Use a filter, not a lens cap. Have juice in the battery and space on the card. And don't reverse your lens hood: if you are hiking and you see a deer, you barely have time to check your exposure settings, you certainly don't have time to be fiddling with a lens hood. Either have it in the forward, shooting position in your bag or don't have it at all. Keep the hood in the original packaging in the original box in case you ever decide to sell the lens - other than that, you probably don't need the hood. If it fits in the forward, shooting position in your bag, great.