I am lobbying for the Thermaltake Core V1. It's smaller than the Corsair while still having all the features.
This build on PCPP is what really convinced me:
http://pcpartpicker.com/b/MsnnTW
Dimensions:
Corsair 13.8 x 10.9 x 11.4 inches = Volume 1714.788
Thermaltake 10.9 x 12.4 x 10.2 inches = Volume 1378.632
gehausthe rvz01 is the tiniest slim itx case ive ever seen to be able to fit a full size gpu and an aio water cooler for the cpu while being half as wide as an atx case and half as tall. you should check it out
Dimensions: Corsair 13.8 x 10.9 x 11.4 inches = Volume 1714.788 Thermaltake 10.9 x 12.4 x 10.2 inches = Volume 1378.632