Hi Mike,Thanks for putting this together. I wanted to do that for a while now, but I guess making you do it perfectly serves the cause as well. :)
As far as ethernet cards, the Intel e1000e *should* be theoretically good, but they seem to fail at properly irq balancing across multiple CPUs on recent kernels, which can cause you to bottleneck at 100% CPU on one core.
I think we have finally solved this. At the moment, CPU usage is good and is not limiting throughput (which could be higher though, not sure if the Tor network is saturated?).
The key was to enable software Receive Packet Steering (RPS) introduced on kernel 2.6.35. I wrote a small howto: http://bit.ly/aqkDvR
== Did I leave anything out? == Well, did I?
At I least I run a manually compiled Tor with OpenSSL 1.0.0 and OpenBSD-malloc enabled. I think Olaf does as well.
-- Moritz http://www.torservers.net/