Sylpheed is good
Now there are two softwares from Japan about which I am in awe. The first one is Ruby programming language. I am searching for something to beat Ruby but I am yet to find out one. There is another one called Sylpheed http://sylpheed.sraoss.jp/en/. Its a email client, and it does its job really well.
Great software these are not coming from capitalistic and human robotising United States, but its now coming out from civilized world which does not destroy life's around the planet just because they have a baseless fear.
I was looking for an alternative to CPU and memory hungry thunderbird, I tested with some other stuff, but Sylpheed turned out to be best. Try it out if you are using Linux.