Blocking is consistantly the biggest problem for us, too. I've written a small application that, every two minutes, checks for blocking on our main sql server. When detected it waits for 15 seconds then checks again. If the same spid(s) is still blocking the app emails me the details about every processid that is blocking or being blocked, including duration, the command being issued, hostname, program, login, etc.

This has allowed us to be extremely proactive in troubleshooting blocking issues. Its funny when we do determine who is running the process that's blocking, call them and suggest something is wrong. "How'd you know?!?!"