Troubleshooting a router sometimes is like voodoo. Knock on wood, but I think I finally got my Linksys E2000 working without issue. I installed DD-WRT on it, and then had some wireless dropouts and freezes after setting up a guest network. Turns out it was user error, I think, as I had forgotten that remnants of an earlier failed attempt to set up the guest network were present in my settings, conflicting with the new settings.
One thing that is both cool and eye-opening about DD-WRT is that it will tell you how many processes are connecting to the Internet on your network. My 7 or 8 devices were responsible for a total of 222 processes, such as my menubar weather app, CrashPlan, Dropbox, etc.