what brand is best??? Big debate.. Bottom line is, you can't go wrong with either canon or nikon. I shoot canon, but they have been proven to be more expensive when it comes to lenses simply because they are the only company that makes their own. Go to Precision and hold both and try shooting with both. What it comes down to is which one is more comfortable to shoot with if you have not had any experience with either. With DSLR you can get better photos, but it is all in the lens and lenses is where you can spend the money. You definitely get what you pay for when it comes to quality. You have more room for post process if you shoot in raw which is an advantage over any point and shoot. I guess the bigger question is what is your budget? You can spend about 400-600 on an entry level DSLR with a cheap lens (kit lens). Lenses can range from 500-4000 depending on what you are wanting to do.
Check out craigslist, they have a big video section. If you get one used online, ask for original receipts of where it was purchased. There are a lot of counterfeits out there. B&H on Amazon are reputable and Precision is as well, but they are more pricey..
Knowledge is key when it comes to photography. There is plenty of it online and there are several people on here that also shoot. Good luck and have fun.
-Jake