[Spakman]

I've had very positive experiences with Mail-in-a-Box for exactly the sort of situation you describe. I think it's a great project that pulls together other packages very nicely.

I was fed up with configuring everything constantly and tuning this, that and the other. These sort of threads always seem to have plenty of people who have a bad time running their own mailserver (and of course your mileage may vary), but I don't really have to touch it at all.