Planck hasn’t launched yet, and it’s a long long way before its results will come out, but it’s the way of space missions to already be thinking of the next step.
BPol was recently proposed to ESA, unsuccessfully, and I’m now at a meeting in the US where a number of possible future CMB satellites are being discussed. A launch in the 2020s is expected. There are also a host of ground-based and balloon borne projects planned between now and then.
Planck will draw the line under temperature fluctuations. The current target is polarization which, it is hoped, can say something about the the inflationary epoch in the first 10-30 seconds after the Big Bang. Exciting stuff, even if it is going to take us a long time to see what the results are!