Sure, getting headers first would
be nice. With an IMAP client this pretty much works for many people.
You can run fetchmail like this. Basically, everytime you want to get
mail you run fetchmail from the command line. If you have a permanent
connection to the net, or nearly permanent (semi automatic, or on
demand dialling or something), this can be a waste of time. Why fetch
the mail when you are waiting to read it? Get the mail before you
reach your terminal!
Typically, in such a scenario, you will run fetchmail as a daemon. In
my case, it polls my POP mailbox every 5 minutes, 24 hours a day, 7
days a week. I never turn off my computer. When I read mail, it is all
there on my local machine. Headers and all. Sure, it takes more
bandwidth, but I'm not billed for bytes transferred, or the the time I
am connected to the network.