More on wheel maintenance, for Matt and everyone else...
Avoid the temptation to buy "Spray on, rinse off, walk away" wheel cleaners at auto parts stores. Most of them don't work very well. And those that do rely on very harsh chemicals to attain their "magic" cleaning ability. I've worked on at least one vehicle - an E39 M5 - where prior use of a product like this badly stained the outer lip of the car's wheels. And one of the wheels on my Mother's MR2 Spyder is discolored now, almost certainly as a result of her using stuff like this. These cleaners will also strip whatever wheel wax you've got on there right off.
Think of wheels like hand washing dishes. Simply rinsing the dishes off doesn't get them truly clean - you need to take a brush, or a sponge, to them, and agitate the food off. The same applies with wheels, or anything on a car.
The best, safest wheel cleaner available is:
P21S Wheel Cleaner Gel. It's very expensive. Chemical Guys also has their
Citrus Sticky Gel Wheel Cleaner, which isn't quite as good, but is a lot more affordable. Finally, a good substitute for the P21S stuff is their companion motorcycle line, S100. It's often the same, or very similar, and costs about half as much. What's more, you can usually find it at the local Harley dealer.
As for what I use? Depends on the wheels. Often it's Meguiar's Wheel Brightener, a highly acidic product that I buy in bulk and cut 4:1 (water:product). It's the strongest stuff on the market, and misuse will ruin the finish on a set of wheels very quickly.
Before:
http://www.esotericdetails.com/images/j ... G_2029.jpg
After:
http://www.esotericdetails.com/images/j ... G_2060.jpg