You can certainly copyright the photos -- in fact, as you are probably aware, copyright attaches automatically. But you can register the copyrights as well.
Now, the fact that the pictures were taken from a public thoroughfare works to your advantage -- the problem will be with the trademarks. I haven't checked, but I would be certain that the casino has a trademark for their name, if nothing else. Does this mean you can't sell the photo -- no. However, it does mean that youmight be limited in how you market the photo. If you go on eBay and try and sell a picture title "Mirage Hotel Las Vegas" or something, that might be suspect, since a consumer might reasonably be confused as to whether this is an official "mirage" photo or not (I know, you are thinking nobody would be confused, but this is what the court will ask). If you can get away in your advertising without naming the names of the casinos, you'll probably be okay. Even a title like "A phot of the Mirage Casino" is likely okay, but nobody can predict how the trademark owner will react, so be prepared.
Finally, if you pictures are a closeup of JUST the name/logo, that might be troublesome. As long as the picture is of the casino, and the name/logo is but an incidental part of the picture, that'll be okay. From a trademark perspective, mind you -- you can always register a copyright here.
