Sometimes email messages have information that belongs somewhere else, like a bug report or a task. I transfer those to the relevant system or document when I receive them.
A folder for each sender is redundant, you can filter your mail and get the same result.
Best is if you can apply the GTD methodology and sort the incoming email in what needs immediate attention, what can wait a bit, etc... I use this with work emails. For my private emails I have a topic based tagging/folder technique.