B and H are one of the greats in the photo/video area. They have virtually everything. You might find a cheaper price somewhere, but this place does not ever try to scam the customer by charging him or her for accessories that are supposed to come with the product (like Abe's, etc.). You really can't go wrong shopping here.
Their website is the most informative in the business. I use it first for a lot of my research. They give a lot of information to help you make informed decisions. It's well organized and the search functions are excellent. I especially like the filters for products to narrow down searches. Compare the website to Adorama (which is an excellent professional supply shop, very much an equivalent company in terms of reputation) and B&H is the clearly more informative and well organized site.
Also, they are very good about returns. Only once was I ever slightly unhappy with a product (a refurbished camera that was a 9 was marked as a used 10) and we resolved everything nicely.
As one of the clerks explained to me, they are just nicer than a lot of other shops. He encouraged me to shop at other stores to find the best price, but also warned that if it's significantly cheaper than their price, it's probably a scam. I've found his advice to be right on target.
My one caveat is a minor one. If you are a working pro in a hurry for stuff, keep a copy of a Jewish calendar. Even the shopping script observes Jewish holidays. It's generally hard to buy a camera on a Jewish holiday anyway, so no surprise there. I think the strong ethical drive behind strict observance of Jewish holidays is reflected in their ethical dealings with customers. On the other hand, if you are in a hurry for a camera and it happens to be Passover, well, you'll have to wait, or go somewhere else.