Well, you must be doing something right, because I've never known a person who owned a black vehicle that wasn't constantly complaining about it being dirty, but those vehicles didn't get babied like yours does. Taking really good care of it is absolutely necessary! Maybe I need to find out what wax you are using, because I get a lot of dust on the back of my C6. Or maybe my four by four-inch pipes could be a contributing factor.
Put the corner of your chamois in a "U" shape (I use the Absorber), and you can tuck it deep under the taillights. I have the same problem with the Trans Am. The water drainage from the hatch routes water through there and the water pools under the lights. Hit the gas, and it drips all down the back of your freshly dried car. I do this every time I wash. I do this with my mirrors as well, because that is another place that water likes to sit.
To the OP -
Lots of other comments going on in here, so I'm just adding my extra cents. I have black wheels on my car, but mine isn't silver. Black wheels is a difficult thing to pull off on a car, if you ask me it totally depends on the car. Black wheels look pretty damn good on a silver Audi, but they look ridiculous on a silver Beetle. Oh wait, anything looks ridiculous on a Volkswagen Beetle, especially the newest 'new' one. Still, hopefully you get my point. Sometimes black looks good on silver, and sometimes it doesn't. And even if you think it looks good, somebody else might not.
Polished and chrome always looks good. I don't particularly like chrome myself, especially on new cars with no chrome anywhere else, but I still have to say that even if I wouldn't do it to my own car, it looks good.