The next pfSense release will be based on FreeBSD 7.0.
One of the biggest:
“In general it can be said that the FreeBSD 7.0 TCP stack is three to five times faster (either in increased speed where not maxed out, or reduced CPU usage). It is no problem to fill either 1 Gb/s or 10 Gb/s links to the max.”
This means you’ll be able to get more throughput out of your existing hardware at that point, and extremely high throughput environments with 10 Gbps links will be possible.
The future looks bright! Kudos to the FreeBSD developers who make projects like pfSense successful with their efforts.