Stevolus

Had a similar issue to this. I found until I gave pfsense a static IP and then under WAN interface, specified the upstream gateway IP, it wouldnt work. Wasnt a train smash for me cos I needed it static for ddns anyway. If you dont come right then change WAN to static and specify upstream gateway and see if that resolves it.

Having a look here, it looks like your specs are fine.. http://www.firewallhardware.it/en/pfsense_selection_and_sizing.html You probably will do fine with switching so long as its not an office full of people, then it may bottleneck I think if alot of people are uploading at gigabit speeds. However as someone mentioned above, consider spending the extra cash on a gigabit switch rather. Best to keep switching and firewalling separate if you can help it in my opinion.