There are a number of good suggestions here already, so I'll take a slightly
different approach. In truth there are a lot of different speakers that will mate
well with the CS, mostly it depends on your budget, your taste, and the type
of muic you listen to.
You should also keep in mind that at least a moderately efficient speaker is
required to make the CS sing. I would not pair it with speakers with an
efficiency rating of less than 87 or 88 db for the best results.
Energy, ProAc, JM Reynaud, Harbeth, Focus Audio, Green Mountain Audio,
PSB, Totem and Paradigm all make speakers that work well with the CS. I'm
sure that Joseph Audio and Reference 3A also work quite well. I think your
problem is going to be more one of narrowing your search as opposed to
finding just one suitable speaker.
Can you provide a little more info with regards to your budgetary and musical
priorities?