I am quite allergic to modern email programs such as Microsoft Outlook, KMail, Evolution or Thunderbird. After digging the web for a mail program that "sucks less", I've adopted mutt. In the same time, I've learned a lot of (not so useful) stuff about the email flow from servers to servers to servers to my brave old Unix mailbox. I am now using a split set of software to manage my emails. This could be confusing at first sight, but eventually I get the so-called do-one-thing-but-do-it-right quality of Unix systems. To summarize it, my messages go through the following path:
.--.
_ -( )- _
.--,( ),--.
_.-( )-._
( INTERNET )
'-._( )_.-'
'__,( ),__'
- ._(__)_. -
^ |
| |
| v
.---------. .-----------.
encryption | stunnel | | getmail | deliver
'---------' '-----------'
^ |
| |
| v
.---------. .----------.
send | postfix | | procmail | filter
'---------' '----------'
^ |
| |
| v
.------. .---------.
read/write | mutt |<============>| dovecot | store
'------' '---------'
Getmail, procmail, dovecot, mutt, postfix and stunnel. That's 6 programs to do what your Microsoft Outlook or Thunderbird do. But I can assure you that the former 6 programs offer a better experience compared to the latter ones.