Thank you both.
Okay, the capacity problem is solved.
For the hardware: The board has no sata ports thats why I would need a raid-controller card. Even if unRaid can not use the special raid features on it(why not?).I just saw that Sata Controller cards without raid features cost the same as the ones with those features...
I would only run tvheadend with DVB-T so there is no HD and the driver for my card is in kernel. Does that solve the problem or do i still need to compile and install the driver myself? Are 512 MB enaugh for that if I let sabnzb and sickbeard go?
@marcusone: So you say it would waste money to buy an additional ethernet card because the speed of all PCI slot together is not high enaugh for both, 3 or 4X SATA and network? Is the 10-12 MB/s enaugh to stream HD movies? (My calculations would say yes: 20GB = 20480 MB for a 90 minute film = 5400 seconds, would be 3,79 MB/s ...)