Hi Mika
My needs are similar to yours:
WAN connection (xDSL modem, connected on the wan port)
WAN2 connection (backup? USB 4G dongle (or 4G router in bridge mode))
Firewall + IDS + SNORT
DHCP server
router/gateway: possibility to route internet traffic to 4G or xDSL, depending on source IP or destination port
WIFI acces point (using pci-e wifi card) or external AccessPoint
LAN connection
samba / OMV / NAS [b]ligth[/b] server
but not a media/headless server
transmisison + sickrage
TV-Headend server
the reason is that i want to make sure that the prime functions (routing + FW) always work while the secondary functions might flood the connection / CPU.