It will support as many hard drives as you have SATA ports (7).
For first-time builders, I recommend looking at these threads while you are waiting for your parts to show up:
Build it yourself:http://www.tomshardware.co.uk/forum/274745-13-step-step-guide-building
And although this primarily a troubleshooting thread, the first part contains a checklist that will catch most noob mistakes:http://www.tomshardware.com/forum/261145-31-read-posting-boot-problems
I also suggest posting budget, primary purchase of the system, and the parts you are considering. There are people here (alas, I am not one
) who are very good at system configuration. For example: if the primary purpose of the system is gaming, selecting a 2500K instead of a 2600K will either save you $100 or, for the same budget, let you get a better video card.