my particular recipe involves fetchmail, procmail, msmtp, vim, aspell, ical, etc..

but yes, if you are stuffing +100k emails into one folder -- that is completely insane -- that's why you use procmail to sort your email into different folders as it arrives; I subscribe to a LOT of email lists and ctrl-D delivers a lot of magic when I don't want to or have the time to sort through a bunch of crap but