...

2) Using the "ip verifiy unicast reverse-path" Cisco feature (it's in 11.1CC images when you use CEF, so I don't get a flood of e-mails)

I'm sure far more people would source filter if Cisco put this in CPE routers.

If I'm not terribly mistaken that'll happen (or has happened, depending on your view) with 12.0. Note that in 12.0, Cisco defaults to "no ip directed-broadcast", a good thing IMHO. - Håvard