Not sure what's recommended for Painted alloys. I don't think things like wonderwheels are good for those. I've been trying wheelwax and so far it seems pretty impressive, cleans reasonably well, and seems to help stop break dust build up. Think i ended up buying some from
http://www.speeding.co.uk it's 20 quid a pot, expensive but so far i seem to be using hardly any, and my alloys look great. you can read more about it at
http://www.wheelwax.com/ i'm definatly glad i decided to try some.