Mark wrote earlier this week about deciding on the best camera to buy. All of today's cameras are better than anything you could buy 10 years ago, so don't get into a religious battle with photographers who tell you there is ONLY one brand to consider. You should buy the camera you feel the most comfortable with. Back in the days of film, I always owned Canons, but switched to Nikon for digital. The feel of their cameras and menu layouts were better for me. I have two additional recommendations for your consideration. The first is to always consider buying the same camera that your friends have. They can help you with questions you will undoubtedly have. They can loan you lenses and other accessories to tryout.
And consider renting the equipment before you buy. You may think that this is expensive, but, if you're talking about buying a DSLR and lenses (easily $1,000), you should be very sure you're going to be happy with your choice. You might think that this is a risky proposition, but there are lots of photographers who would tell you otherwise.
My personal experience with LensRentals.com has been very positive. Last weekend, we shot a wedding on the beach in Cape Hatteras, North Carolina, and I wanted to have a second camera with me. (I really wanted Nikon to release the D4 a few months ago, there still has been no announcement about a D3 replacement.) I rented a D300S, with its greater low-light sensitivity, but still very similar in other features to my D300. I threw in a battery grip and Nikkor 16-35mm wide angle zoom for some extra pizzazz. Everything arrived on the proper date, and the gear was as good as new, with no scratches or problems. I enjoyed the experience, and the total was far less than the cost of a new lens. And, yes, they do rent Canon equipment...and Sony, Leica, and Hasselblad. There are many other companies that have similar services. I have heard good reports about BorrowLenses.com, too. They rent Nikon, Canon, and Sony equipment.
If you rent, make sure you know when the equipment will arrive. Mine was shipped UPS, and, because of the value of the equipment, a signature was required. Luckily, LensRentals sent me an email with a reminder, and I was there. I bought the insurance for extra safety, as well. The replacement cost of the gear was more than I wanted to risk. The return was easy, with a supplied pre-printed label and a trip around the corner to the UPS.
So, next time you are deciding whether or not to plunk down some of your hard-earned cash for a new piece of camera gear, consider renting first. But beware - it can have some bad effects, too. Now I want the new Nikon AND a 16-35mm lens.