Who needs Yahoo! anyway?
But if you're an addict check this possibility out:
http://help.yahoo.com/l/ca/yahoo/mail/pop/pop-01.html
On Ubuntu I've found Evolution to be superior to anything else but I did get frequent crashes with 9.04. Not tried it since my upgrade to 9.10 because I'm currently looking at 2.0 of Seamonkey. I've always preferred an integrated client and used Opera extensively on Vista because having Thunderbird open used to eat up resources and just bug me. I do like this latest version of Seamonkey though but of course it won't suit everyone.