For Yahoo, I currently have 3 accounts that I use - 1 is for some-what important e-mail/newsletters. The other 2 are disposable account where I use to sign up for free things, etc... where the junk can fill & I know I can just go there every month or so and just delete everything... without reading.

Actually for all important everyday mail, I keep a private ISP address - well it's not too private, but given out a lot less then the "disposable" accounts. :-)