I think the black wheels work best with white, silver, grey and darker colours, not red the blues; whereas the silver wheels work well with everything. Titanium wheels would be fine, but black is just too bling for me.
Personally, I prefer the optional multi-spoke wheels you could specify for the R32 to the Audi / Porsche lookalikes that come with the R. As things stand, I will order 19" silver alloys for my R.