Do you use a NIkon or Canon DSLR?

Which one and why did you choose that to get that dslr?

Canon 7d, choose it because i'm familiar with how it works, and generally that is really all there's in it, each has it's own particular quirk you buy for, not much in build quality these days they are pretty much the same

Currently shooting Canon because at the time I bought my first DSLR (Canon 40D), most of my friends who were professionals, were shooting Canon and were willing to loan their lenses and other equipment to me while I learned. My interest at the time was shooting sports and a comparable Nikon body at that time cost $600 more than what I spent on the 40D.

Today, I'd probably shoot Nikon because there are certain features I prefer in their D300s, D700 and D3 series bodies compared to my current 7D and 5D Mark II Canon bodies. At the end of the day however, changing to Nikon wouldn't improve my image quality and would be too costly because I have well over $10, 000 invested in Canon lenses and speedlites, let alone the camera bodies.

My suggestion to you however, is set a budget. Be sure to factor in the cost of lenses, speedlights/flashes, and other accessories. Then figure out which bodies from both manufactures fit in this budget. Finally, head to your nearest camera shop that carries those bodies and try them for yourself. You might find that your prefer Nikon. Or, you may decide you find Canon easier to use. Again, it's mostly about personal preference. I'm happy with Canon and I'm not compelled to change. There are people who feel the same way about Nikon and all I can say is more power to them. The two brands offer near absolute parity for any given lens, including tilt-shift/perspective control lenses. So there's not much you can do with one brand that you can't do with the other. Your choices for lenses and other accessories are a little more limited with other brands in that regard which is part of the reason Canon and Nikon remain the professional standard. I don't think you can go wrong with either brand.

Nikon

because my dad uses Nikon

he chose Nikon because he liked the feel of the D300

Canon. I have a working pro friend here in town who won't use anything but Nikon and we're both very happy with our gear.

Canon
Dad used it, friends use it, we share our gears.

I have a canon eos rebel. Its my first dSLR and its easy to use and takes good pictures! I like it a lot and it was pretty affordable in the bundle deal i got it in.

Canon T1i and 5DM2 with the 1DMiv on order. I also have a Sony point and shoot and a Sony Digital video Camera. Why Canon? No real reason, I could have easily gone for Nikon instead but I have no regrets. Wish list: Waiting for the 5DM3 and the 200-400f4L IS. If there's not a big improvement in the 5DM3 over the 2, I'll buy the much anticipated1Ds4 instead. We'll see.

I use Olympus (and sometimes Nikon). Why? Because I feel more comfortable with Olympus and I can get desired results with it rather easily. I like Nikon and Canon as well, but I sometimes feel they are over-priced and I always strictly never buy anything over-priced, whether it's Apple Mac, SonyVaio, Canon, Nikon etc.
But I have no problem recommending Canon and Nikon, because I know they are good cameras.

I once used a Nikkorex F with an AF 50mm f/1.8. The Nikkorex weighed like a tank so I had to use the lightest lens I had on it. I used that setup for my dirty work when I needed to shoot with waist deep in water, lying on the grass, dirt or sand. They did the job quite well and served their purpose. Both were secondhand when I got them so I wasn't surprised when the tank broke. The lens however survives and is now a part of my son's D50 gear.