I purchased mine from B&H Photo and Video. They may not have the best price but they are very competitive and you have to be careful as there is a lot of gray market stuff out there.
Stay away from any of the vendors that ask you to call in and verify your order only to try and sell you cheap knock off accessories for huge premiums. Butterfly Photo was one that was like that. They offered the camera for almost a thousand dollars less and said in stock but when people refused the extras they put them on indefinite back-order.
I would stick with a trusted vendor and pay a little more just to be certain you are not getting a refurbished item or a gray market knock-off.
Well I gata agree...I've been buying my cameras from B&H photo for at least 20 years.
They are the best store you can go to to buy a camera.
They also offer free parking in the city...that's a $35 - $50 savings right there.
Please check the website for details.
They also will ship to your house in you don't want to drive across the river.
I also agree that they don't drop prices as fast as some others but for a 5D you'll get a competitive price.
I also have had good experiences with B & H. I bought mine from Robert's in INdiana, FWIW, they had a better price at the time. Most of my lenses have come from B & H.