LOVE pfSense. I run it on a dedicated microATX PC with 4 GB RAM and a 60 GB SSD, and even with firewall logging turned on, I get pretty darn close to the maximum on my 1 GBps LAN. I would never go back to consumer/retail-grade equipment again.
dd-wrt for me. I have a slow net connection relatively speaking but it streams 720 fine so no need to upgrade.