CPU, GPU (possiblity of SLI when it appears), chipset, hard drives (3+) and PSU.
My system cools CPU,GPU, Chipset, 3 HDDs and has more than 5 Meters of Pipes (?) and the 1046 is much more than enough for this System.
If you want to use the Cuplex pro, a 1048 may be better, but i think that even in this case the 1046 is enough.