Need guidance in choosing mail-client

[Joachim Dagerot]

I am using Evolution as it is now, I have never tried any other
mailclients for X.

I do miss an oportunity to choose sender each time I post a message,
only way to solve that is to set up multiple accounts, and that
certainly don't affect me.

In Evolution it's basically only the "sort messages in thread" that's
really useful.


Based on the two criterias above (Possibility to have multiple sender
addresses on one account, and messages sorted in threads) can you give
me some hints on good software?