This morning, I woke up to the equivalent of a nuclear holocaust on my network. Everything was down, nothing was connecting to nowhere. Eventually, I tracked it down to my old Buffalo router which I've had running for 3 years with DD-WRT. I gave it a hard reset, and it seemed to do, but it seemed like there was still something not right.. I updated it from v24 to v24 SP2, and it was nice to upgrade it but I was still missing my WDS with the ASUS router I have in the basement.
Then I googled upon this: http://ftp.dd-wrt.com/phpBB2/viewtopic.php?p=315423&sid=cc6c26062a9e0dec854c9f3ad42bfc26 and the solution at the bottom pointed exactly to what I had going on. I was using WPA2 Mixed Personal, but it seems there's a bit of a connection issue with that and WDS. Once I changed the settings on both routers to WPA Personal, they saw each other again, and all is well in the world... mostly.
I also now need to etch in stone some static addresses, namely for my Server and Desktop!